[New Check]: Add experimenter form check using DANDI regex

[CodyCBakerPhD]

fix #33

Checks the text form of each experimenter against the DANDI regex pattern (imported directly from there in case they ever update it).

Check has early return in the event that DANDI is not installed (with informative warning message).

Also incorporates that byte-string fix we needed for publications, which has a similar kind of structure to this.

[CodyCBakerPhD]

Oh yeah, SS of how the warning appears (in a small window anyway):

EDIT: Not applicable any more

[codecov-commenter]

Codecov Report

Merging #227 (b15600c) into dev (1d35700) will increase coverage by 0.38%.
The diff coverage is 88.46%.

@@            Coverage Diff             @@
##              dev     #227      +/-   ##
==========================================
+ Coverage   94.45%   94.83%   +0.38%     
==========================================
  Files          16       17       +1     
  Lines         865      890      +25     
==========================================
+ Hits          817      844      +27     
+ Misses         48       46       -2     

Flag	Coverage Δ
unittests	94.83% <88.46%> (+0.38%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
nwbinspector/checks/images.py	86.66% <86.66%> (ø)
nwbinspector/checks/nwbfile_metadata.py	98.80% <90.90%> (-1.20%)	⬇️
nwbinspector/nwbinspector.py	93.50% <0.00%> (+1.00%)	⬆️
nwbinspector/utils.py	89.04% <0.00%> (+4.10%)	⬆️