feat: Added proper scopes to media routes

[frgfm]

Following up on #45, this PR introduces the following modifications:

• renamed the media upload route
• added admin scope to media get and fetch routes
• reindented the table in the media route

Any feedback is welcome!

Note: I think there is an issue with our unittests regarding Security/get_current_access. When I test it manually, the changes from this PR do work. But this means that the current unittests should fail (because the default current access doesn't have admin scope). I'll open an issue about this #119

[codecov]

Codecov Report

Merging #118 (f397f66) into master (a139a8c) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #118   +/-   ##
=======================================
  Coverage   88.31%   88.31%           
=======================================
  Files          27       27           
  Lines         787      787           
=======================================
  Hits          695      695           
  Misses         92       92           

Flag	Coverage Δ
unittests	88.31% <100.00%> (ø)

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Impacted Files	Coverage Δ
src/app/api/routes/media.py	87.50% <100.00%> (ø)

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