Add Ruff and Basedpyright linters to (the newer) Python scripts in Mbed

[multiplemonomials]

Summary of changes

This PR adds some linting support for the Python scripts in Mbed. It might seem like a small thing, but I believe linters like Ruff and pyright are a great way to catch small mistakes before they become a problem (especially in a language like Python that lets you play it fast and loose with types). I don't really expect to catch bugs in the existing scripts, as those have been working for some time, but I really want to have the linter available when making my own changes and additions to these scripts down the road.

Note that for now I only added the linters to the newest python scripts, the mbed_tools and mbed_platformio packages. The old scripts are largely deprecated and don't have any type annotations, so I feel like linting those would be a significant uphill battle, and I'd want to prune out a lot of the unused ones first.

Impact of changes

• All mbed_tools and mbed_platformio python code now passes linters
• Removed a fair bit of old unused code in mbed_tools, like code that creates placeholder CMakeLists.txt files and code that downloads Mbed and its libraries from Git repos
• Lots of common issues/quirks were resolved in the code, either fully automatically or manually based on what the linter flagged:
  • Functions that act as overrides but are missing the @override decorator now have it (and their arguments are made to match exactly with the base class function)
  • Exception messages now get saved into a variable before the exception is thrown to clean up the stacktrace
  • All imports are now sorted
  • All exception class names now end with -Error

Migration actions required

Documentation

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Pull request type

[] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[X] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

[] No Tests required for this change (E.g docs only update)
[X] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

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