BUG: pd.tseries.frequencies.to_offset() does not really provide a DateOffset object
- [X] I have checked that this issue has not already been reported.

- [X] I have confirmed this bug exists on the latest version of pandas.

- [ ] (optional) I have confirmed this bug exists on the master branch of pandas.

---
**Note**: Please read [this guide](https://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports) detailing how to provide the necessary information for us to reproduce your bug.

#### Code Sample, a copy-pastable example

```python
import pandas as pd
from datetime import datetime
data=pd.DataFrame([[430., 630.],
                         [540., 660.],
                         [610., 720.]],
                        columns=[1, 2],
                        index=pd.date_range(datetime(2019, 1, 1, 12),
                                            datetime(2019, 1, 1, 12, 30),
                                            freq='15min'))
pd.tseries.frequencies.to_offset(pd.infer_freq(data.index))
>> <15 * Minutes>
pd.tseries.frequencies.to_offset(pd.infer_freq(data.index)) / 2
>> <450 * Secondes>
pd.tseries.offsets.DateOffset(minutes=15)
>> <DateOffset: minutes=15>
pd.tseries.offsets.DateOffset(minutes=15) / 2
>> TypeError: unsupported operand type(s) for /: 'DateOffset' and 'int'

```
#### Problem description
The function `pd.tseries.frequencies.to_offset` does not really provide a `DateOffset`object. As I understand the code right there are several types of DateOffsets e.g. Minutes, Seconds that are not compareable with the DateOffset object because they are having different properties.



#### Expected Output
One Unified pd.DateOffset Object with same properties for all inherit Objects like Minutes and Seconds
#### Output of ``pd.show_versions()``

<details>

[INSTALLED VERSIONS
------------------
commit           : None
python           : 3.6.9.final.0
python-bits      : 64
OS               : Linux
OS-release       : 4.15.0-99-generic
machine          : x86_64
processor        : x86_64
byteorder        : little
LC_ALL           : None
LANG             : de_DE.UTF-8
LOCALE           : de_DE.UTF-8

pandas           : 1.0.3
numpy            : 1.16.0
pytz             : 2018.9
dateutil         : 2.8.1
pip              : 20.0.2
setuptools       : 44.0.0
Cython           : 0.28.3
pytest           : 4.3.0
hypothesis       : None
sphinx           : None
blosc            : None
feather          : None
xlsxwriter       : None
lxml.etree       : 4.2.1
html5lib         : 0.999999999
pymysql          : 0.9.3
psycopg2         : 2.8.4 (dt dec pq3 ext lo64)
jinja2           : 2.10
IPython          : 7.11.1
pandas_datareader: None
bs4              : 4.6.0
bottleneck       : 1.3.0
fastparquet      : None
gcsfs            : None
lxml.etree       : 4.2.1
matplotlib       : 2.2.2
numexpr          : 2.6.4
odfpy            : None
openpyxl         : None
pandas_gbq       : None
pyarrow          : 0.13.0
pytables         : None
pytest           : 4.3.0
pyxlsb           : None
s3fs             : None
scipy            : 1.4.1
sqlalchemy       : 1.3.16
tables           : 3.4.2
tabulate         : 0.8.5
xarray           : 0.10.9
xlrd             : 1.1.0
xlwt             : None
xlsxwriter       : None
numba            : 0.42.0
]

</details>
