PERF: speed up PeriodArray creation by exposing dayfirst/yearfirst params
As much of the time creating a `PeriodArray` from `int`s is actually spent importing/querying `get_option('display.date_dayfirst')` and its `yearfirst` cousin, this PR exposes those parameters in `Period.__new__()` to allow them to be queried once per array creation.

This yields a ~15x speedup:
```
asv compare upstream/master HEAD -s --sort ratio

Benchmarks that have improved:

       before           after         ratio
     [210538e4]       [32288230]
     <period_dayfirst~1>       <period_dayfirst>
-       102±0.9ms       7.08±0.2ms     0.07  period.PeriodIndexConstructor.time_from_ints('D', True)
-         101±2ms       6.56±0.3ms     0.06  period.PeriodIndexConstructor.time_from_ints('D', False)
```
- [ ] closes #xxxx
- [x] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry
