Remove dependency on six

[oddstr13]

Remove all usage of six and kodi_six.

• Squash commits?
• Add commits to ignore?

A few changes have potential of maybe being functional, but I don't think they are in modern python/kodi versions.

[codecov]

Codecov Report

Attention: Patch coverage is 64.35644% with 36 lines in your changes missing coverage. Please review.

Project coverage is 21.50%. Comparing base (1910de8) to head (876e940).
Report is 12 commits behind head on master.

Files	Patch %	Lines
jellyfin_kodi/library.py	20.00%	12 Missing ⚠️
jellyfin_kodi/entrypoint/default.py	0.00%	7 Missing ⚠️
jellyfin_kodi/helper/utils.py	66.66%	2 Missing and 1 partial ⚠️
jellyfin_kodi/database/__init__.py	50.00%	2 Missing ⚠️
jellyfin_kodi/jellyfin/http.py	0.00%	2 Missing ⚠️
jellyfin_kodi/objects/obj.py	50.00%	2 Missing ⚠️
jellyfin_kodi/dialogs/context.py	66.66%	1 Missing ⚠️
jellyfin_kodi/dialogs/loginmanual.py	50.00%	1 Missing ⚠️
jellyfin_kodi/dialogs/serverconnect.py	66.66%	1 Missing ⚠️
jellyfin_kodi/dialogs/servermanual.py	50.00%	1 Missing ⚠️
... and 4 more

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #880   +/-   ##
=======================================
  Coverage   21.49%   21.50%           
=======================================
  Files          63       63           
  Lines        8626     8632    +6     
  Branches     1586     1585    -1     
=======================================
+ Hits         1854     1856    +2     
- Misses       6748     6755    +7     
+ Partials       24       21    -3     

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[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
1.3% Duplication on New Code

See analysis details on SonarCloud

[oddstr13]

The internal restart/reload addon function seems to be broken, but I don't think that is caused by this PR.
Fixing it is out of scope for this PR in any case.