Feat/filer perm improvements

[vinitkumar]

Description

Implement some permissions related fixes for the filer.

Related resources

Refer to issue, resolves #1358

Checklist

• [x] I have opened this pull request against master
• [x] I have added or modified the tests when changing logic
• [x] I have followed the conventional commits guidelines to add meaningful information into the changelog
• [x] I have read the contribution guidelines and I have joined #workgroup-pr-review on Slack to find a “pr review buddy” who is going to review my pull request.

[codecov[bot]]

Codecov Report

Merging #1359 (ba97a1a) into master (e920e55) will decrease coverage by 0.01%. The diff coverage is 75.00%.

@@            Coverage Diff             @@
##           master    #1359      +/-   ##
==========================================
- Coverage   72.41%   72.40%   -0.01%     
==========================================
  Files          72      144      +72     
  Lines        3284     6571    +3287     
  Branches      534     1008     +474     
==========================================
+ Hits         2378     4758    +2380     
- Misses        739     1476     +737     
- Partials      167      337     +170     

Impacted Files	Coverage Δ
filer/models/virtualitems.py	92.10% <66.66%> (-2.27%)	:arrow_down:
filer/admin/folderadmin.py	71.94% <100.00%> (ø)
filer/models/foldermodels.py	85.99% <100.00%> (ø)

... and 72 files with indirect coverage changes