CLN: ASV inference benchmark
- Flake8 and removed star imports

- Used `params` and `setup_cache` where possible

```
asv dev -b ^inference
· Discovering benchmarks
· Running 13 total benchmarks (1 commits * 1 environments * 13 benchmarks)
[  0.00%] ·· Building for existing-py_home_matt_anaconda_envs_pandas_dev_bin_python
[  0.00%] ·· Benchmarking existing-py_home_matt_anaconda_envs_pandas_dev_bin_python
[  0.00%] ··· Setting up /home/matt/Projects/pandas-mroeschke/asv_bench/benchmarks/inference.py:105
[  7.69%] ··· Running inference.MaybeConvertNumeric.time_convert                                                                    2.55s
[ 15.38%] ··· Running inference.NumericInferOps.time_add                                                                               ok
[ 15.38%] ···· 
               ========= ========
                 dtype           
               --------- --------
                 int64    7.27ms 
                 int32    4.09ms 
                 uint32   2.33ms 
                float32   3.98ms 
                float64   7.20ms 
               ========= ========

[ 23.08%] ··· Running inference.NumericInferOps.time_divide                                                                            ok
[ 23.08%] ···· 
               ========= ========
                 dtype           
               --------- --------
                 int64    9.22ms 
                 int32    7.77ms 
                 uint32   6.34ms 
                float32   4.00ms 
                float64   7.25ms 
               ========= ========

[ 30.77%] ··· Running inference.NumericInferOps.time_modulo                                                                            ok
[ 30.77%] ···· 
               ========= ========
                 dtype           
               --------- --------
                 int64    17.3ms 
                 int32    9.96ms 
                 uint32   10.3ms 
                float32   8.27ms 
                float64   8.37ms 
               ========= ========

[ 38.46%] ··· Running inference.NumericInferOps.time_multiply                                                                          ok
[ 38.46%] ···· 
               ========= ========
                 dtype           
               --------- --------
                 int64    7.18ms 
                 int32    4.12ms 
                 uint32   2.42ms 
                float32   4.08ms 
                float64   7.15ms 
               ========= ========

[ 46.15%] ··· Running inference.NumericInferOps.time_subtract                                                                          ok
[ 46.15%] ···· 
               ========= ========
                 dtype           
               --------- --------
                 int64    7.23ms 
                 int32    3.96ms 
                 uint32   2.36ms 
                float32   3.96ms 
                float64   7.12ms 
               ========= ========

[ 53.85%] ··· Running inference.ToNumeric.time_from_float                                                                              ok
[ 53.85%] ···· 
               ======== =======
                errors         
               -------- -------
                ignore   157μs 
                coerce   158μs 
               ======== =======

[ 61.54%] ··· Running inference.ToNumeric.time_from_numeric_str                                                                        ok
[ 61.54%] ···· 
               ======== ========
                errors          
               -------- --------
                ignore   8.08ms 
                coerce   8.05ms 
               ======== ========

[ 69.23%] ··· Running inference.ToNumeric.time_from_str                                                                                ok
[ 69.23%] ···· 
               ======== ========
                errors          
               -------- --------
                ignore   365μs  
                coerce   24.7ms 
               ======== ========

[ 76.92%] ··· Running inference.ToNumericDowncast.time_downcast                                                                        ok
[ 76.92%] ···· 
               ============== ======== ========= ======== ========== ========
               --                                 downcast                   
               -------------- -----------------------------------------------
                   dtype        None    integer   signed   unsigned   float  
               ============== ======== ========= ======== ========== ========
                string-float   264ms     270ms    272ms     267ms     268ms  
                 string-int    597ms     621ms    640ms     612ms     605ms  
                string-nint    613ms     622ms    631ms     597ms     610ms  
                 datetime64    5.17ms    72.0ms   72.3ms    74.3ms    8.87ms 
                  int-list     65.0ms    92.7ms   92.5ms    94.5ms    66.8ms 
                   int32       26.2μs    27.2ms   26.9ms    27.9ms    1.35ms 
               ============== ======== ========= ======== ========== ========

[ 76.92%] ··· Setting up /home/matt/Projects/pandas-mroeschke/asv_bench/benchmarks/inference.py:40
[ 84.62%] ··· Running inference.DateInferOps.time_add_timedeltas                                                                   29.1ms
[ 92.31%] ··· Running inference.DateInferOps.time_subtract_datetimes                                                               23.6ms
[100.00%] ··· Running inference.DateInferOps.time_timedelta_plus_datetime                                                           157ms
```
