misc: split database and added docs

[baszalmstra]

It required some effort to understand the codebase so I thought it was time to add a bunch of documentation. I also split some of the databases into different databases to get a better grouping.

[codecov]

Codecov Report

Merging #267 into master will decrease coverage by 0.03%.
The diff coverage is 33.33%.

@@            Coverage Diff             @@
##           master     #267      +/-   ##
==========================================
- Coverage   79.08%   79.05%   -0.04%     
==========================================
  Files         214      214              
  Lines       12803    12808       +5     
==========================================
  Hits        10125    10125              
- Misses       2678     2683       +5     

Impacted Files	Coverage Δ
crates/mun_codegen/src/mock.rs	82.05% <0.00%> (-4.44%)	⬇️
crates/mun_compiler/src/db.rs	47.05% <0.00%> (-6.28%)	⬇️
crates/mun_compiler/src/driver.rs	59.76% <ø> (ø)
crates/mun_hir/src/expr/validator/tests.rs	100.00% <ø> (ø)
crates/mun_hir/src/mock.rs	85.71% <0.00%> (-5.20%)	⬇️
crates/mun_hir/src/ty/tests.rs	96.51% <ø> (ø)
crates/mun_language_server/src/db.rs	10.71% <0.00%> (-0.83%)	⬇️
crates/mun_language_server/src/diagnostics.rs	0.00% <ø> (ø)
crates/mun_hir/src/db.rs	100.00% <100.00%> (ø)
crates/mun_hir/src/in_file.rs	45.45% <100.00%> (ø)
... and 1 more

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[Wodann]

Good to have this documentation, and the code is also a lot more concise. Thanks for this!

How did you make the diagram? I like the style! 🙂

[baszalmstra]

How did you make the diagram? I like the style! 🙂

It's basically draw.io with a custom font: https://drawio-app.com/introducing-draw-ios-new-sketch-feature/
The font is: https://fonts.google.com/specimen/Indie+Flower