[WIP]: Remove DummyContext

[tbkr]

Description

This is a WIP branch to get rid of the context in all of the expansion methods. The call tree relied on a DummyContext object being passed through several layers of the Code. There was no usage in the inner functions, rendering the object useless. I removed it form the function definitions.

Contributor Declaration

By opening this pull request, I affirm the following:

• All authors agree to the Contributor License Agreement.
• The code follows the project's coding standards.
• I have performed self-review and added comments where needed.
• I have added or updated tests to verify that my changes are effective and functional.
• I have run all existing tests and confirmed they pass.

[tbkr]

Waiting for the CICD to see whether parts of the stack were relying on the functionality (I only checked the mars-client-bundle so far).

[codecov-commenter]

Codecov Report

❌ Patch coverage is 91.40625% with 11 lines in your changes missing coverage. Please review.
✅ Project coverage is 68.73%. Comparing base (b403143) to head (a75f8b7).

Files with missing lines	Patch %	Lines
src/metkit/mars/MarsExpansion.cc	54.54%	5 Missing ⚠️
src/metkit/mars/Type.cc	81.81%	2 Missing ⚠️
src/metkit/mars/TypeParam.cc	71.42%	2 Missing ⚠️
src/metkit/mars/MarsLanguage.cc	90.90%	1 Missing ⚠️
src/metkit/mars/Parameter.cc	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #106      +/-   ##
===========================================
+ Coverage    68.32%   68.73%   +0.41%     
===========================================
  Files          124      126       +2     
  Lines         7340     7382      +42     
  Branches       732      731       -1     
===========================================
+ Hits          5015     5074      +59     
+ Misses        2325     2308      -17     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[simondsmart]

I'd like to have a chat with you/Emanuele about this one. I think I would have to do a lot of reading before I could review it on-spec.