feat: insight cog

[HadesArmy]

Summary

close #95

Checklist

• [ ] This PR fixes an issue.
• [x] This PR adds something new (e.g. new method or parameters).
• [ ] This PR is a breaking change (e.g. methods or parameters removed/renamed)
• [ ] This PR is not a code change (e.g. documentation, README, ...)

• [x] Have you tested the changes? (pytest & dpytest)
• [x] Have you followed PEP-8 for naming and styling?
• [x] Has your code been properly documented with RestructuredText docstrings?
• [x] Have you added your changes to CHANGELOG.md under the [Unreleased] heading?
• [ ] If your code added new bot commands, have you updated documentation.json?

• [x] All of this code is your own, or follows the author repo's licence.

[codecov[bot]]

Codecov Report

Merging #423 (d705df6) into master (7ef2898) will increase coverage by 0.14%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #423      +/-   ##
==========================================
+ Coverage   87.35%   87.49%   +0.14%     
==========================================
  Files         125      130       +5     
  Lines        9110     9214     +104     
==========================================
+ Hits         7958     8062     +104     
  Misses       1152     1152              

Flag	Coverage Δ
unittests	87.49% <100.00%> (+0.14%)	:arrow_up:

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

Files	Coverage Δ
koala/cogs/__init__.py	100.00% <100.00%> (ø)
koala/cogs/insights/__init__.py	100.00% <100.00%> (ø)
koala/cogs/insights/cog.py	100.00% <100.00%> (ø)
koala/cogs/insights/core.py	100.00% <100.00%> (ø)
koala/cogs/insights/log.py	100.00% <100.00%> (ø)
koalabot.py	74.13% <100.00%> (ø)
tests/cogs/insights/test_cog.py	100.00% <100.00%> (ø)