Chore: clean up dead imports

[esqew]

There are quite a few spots around the codebase where we have imports that aren't being used.

Since this is purely cosmetic & isn't a drag on performance (at least, not to my knowledge) this one will be prioritized pretty low.

Also a good first ticket for those so inclined to jump in.

[esqew]

Flake8's got a list for us to go on:

$ python3 -m flake8 . --select=F401
./kenpompy/FanMatch.py:5:1: F401 'mechanicalsoup' imported but unused
./kenpompy/FanMatch.py:7:1: F401 'bs4.BeautifulSoup' imported but unused
./kenpompy/conference.py:6:1: F401 'mechanicalsoup' imported but unused
./kenpompy/conference.py:8:1: F401 're' imported but unused
./kenpompy/conference.py:9:1: F401 'bs4.BeautifulSoup' imported but unused
./kenpompy/conference.py:10:1: F401 'datetime' imported but unused
./kenpompy/misc.py:6:1: F401 'mechanicalsoup' imported but unused
./kenpompy/misc.py:8:1: F401 'bs4.BeautifulSoup' imported but unused
./kenpompy/summary.py:6:1: F401 'mechanicalsoup' imported but unused
./kenpompy/summary.py:9:1: F401 'bs4.BeautifulSoup' imported but unused
./tests/test_conference.py:1:1: F401 'pytest' imported but unused
./tests/test_conference.py:2:1: F401 'datetime' imported but unused
./tests/test_conference.py:4:1: F401 'pandas as pd' imported but unused
./tests/test_fanmatch.py:1:1: F401 'pytest' imported but unused
./tests/test_fanmatch.py:2:1: F401 'kenpompy.misc as kpmisc' imported but unused
./tests/test_fanmatch.py:4:1: F401 'pandas as pd' imported but unused
./tests/test_misc.py:3:1: F401 'kenpompy.FanMatch.FanMatch' imported but unused
./tests/test_misc.py:4:1: F401 'pandas as pd' imported but unused
./tests/test_summary.py:3:1: F401 'pandas as pd' imported but unused
./tests/test_team.py:5:1: F401 'pandas as pd' imported but unused