Support trait methods and trait default implementations

[fzyzcjy]

Changes

Please list issues fixed by this PR here, using format "Fixes #the-issue-number".

Checklist

• An issue to be fixed by this PR is listed above.
• New tests are added to ensure new features are working. Please refer to this page to see how to add a test.
• ./frb_internal precommit --mode slow (or fast) is run (it internal runs code generator, does auto formatting, etc).
• If this PR adds/changes features, documentations (in the ./website folder) are updated.
• CI is passing. Please refer to this page to see how to solve a failed CI.

Remark for PR creator

• ./frb_internal --help shows utilities for development.
• If fzyzcjy does not reply for a few days, maybe he just did not see it, so please ping him.

[codecov]

Codecov Report

Attention: Patch coverage is 95.81590% with 10 lines in your changes missing coverage. Please review.

Project coverage is 97.98%. Comparing base (7b41a28) to head (11d58ae).
Report is 10 commits behind head on master.

❗ Current head 11d58ae differs from pull request most recent head 5e9241b

Please upload reports for the commit 5e9241b to get more accurate results.

Files	Patch %	Lines
...rc/library/codegen/ir/hir/hierarchical/function.rs	86.84%	5 Missing ⚠️
.../library/codegen/parser/mir/function_parser/mod.rs	90.32%	3 Missing ⚠️
...rarchical/pack/third_party_override_transformer.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2024      +/-   ##
==========================================
+ Coverage   97.79%   97.98%   +0.19%     
==========================================
  Files         416      419       +3     
  Lines       16900    16992      +92     
==========================================
+ Hits        16527    16650     +123     
+ Misses        373      342      -31     

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