Deprecate some analysis functions

[freemansw1]

As discussed in #146 (and similar to #200), this deprecates three functions in analysis.py: cell_statistics_all, cell_statistics, and cog_cell. These functions likely don't work and should be reworked in any event before 2.0.

• Have you followed our guidelines in CONTRIBUTING.md?
• Have you self-reviewed your code and corrected any misspellings?
• Have you written documentation that is easy to understand?
• Have you written descriptive commit messages?
• Have you added NumPy docstrings for newly added functions?
• Have you formatted your code using black?
• If you have introduced a new functionality, have you added adequate unit tests?
• Have all tests passed in your local clone?
• If you have introduced a new functionality, have you added an example notebook?
• Have you kept your pull request small and limited so that it is easy to review?
• Have the newest changes from this branch been merged?

[codecov]

Codecov Report

Base: 39.03% // Head: 39.01% // Decreases project coverage by -0.02% ⚠️

Coverage data is based on head (672abbc) compared to base (7e961e6).
Patch coverage: 25.00% of modified lines in pull request are covered.

Additional details and impacted files

@@              Coverage Diff              @@
##           RC_v1.5.0     #207      +/-   ##
=============================================
- Coverage      39.03%   39.01%   -0.03%     
=============================================
  Files             11       11              
  Lines           2262     2266       +4     
=============================================
+ Hits             883      884       +1     
- Misses          1379     1382       +3     

Flag	Coverage Δ
unittests	39.01% <25.00%> (-0.03%)	⬇️

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

Impacted Files	Coverage Δ
tobac/analysis.py	8.15% <25.00%> (+0.24%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[snilsn]

Agree with the deprecation of these functions @freemansw1 . Approving this PR

[JuliaKukulies]

Me, too! Happy for you to merge as soon as you are ready @freemansw1