feat: Automatically create indexes for `_Session.sessionToken` and class relations

[dblythy]

New Pull Request Checklist

• [x] I am not disclosing a vulnerability.
• [x] I am creating this PR in reference to an issue.

Issue Description

Parse Server does not create indexes on the _Session class and join tables.

Closes: #8290 Closes: #7832

Approach

Adds indexes

TODOs before merging

• [x] Add tests

[parse-github-assistant[bot]]

I will reformat the title to use the proper commit message syntax.

[parse-github-assistant[bot]]

Thanks for opening this pull request!

• 🎉 We are excited about your hands-on contribution!

[codecov[bot]]

Codecov Report

Base: 94.04% // Head: 93.86% // Decreases project coverage by -0.17% :warning:

Coverage data is based on head (36f658d) compared to base (b1bb1fc). Patch coverage: 78.37% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##            alpha    #8346      +/-   ##
==========================================
- Coverage   94.04%   93.86%   -0.18%     
==========================================
  Files         181      181              
  Lines       14266    14303      +37     
==========================================
+ Hits        13416    13426      +10     
- Misses        850      877      +27     

Impacted Files	Coverage Δ
src/SchemaMigrations/DefinedSchemas.js	87.89% <0.00%> (-0.94%)	:arrow_down:
src/Controllers/DatabaseController.js	93.39% <82.85%> (-0.53%)	:arrow_down:
src/GraphQL/loaders/filesMutations.js	41.93% <0.00%> (-38.71%)	:arrow_down:
src/GraphQL/transformers/mutation.js	87.85% <0.00%> (-9.35%)	:arrow_down:
...dapters/Storage/Postgres/PostgresStorageAdapter.js	95.95% <0.00%> (+0.22%)	:arrow_up:

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[mtrezza]

@Moumouls Do you want to review this before we merge?

[Moumouls]

here some feedbacks @dblythy @mtrezza

[Moumouls]

@dblythy are you still interested to push this one ? :)