Improve Github labels for NuttX

[raiden00pl]

Description

Currently, the labels are not very readable. There is too much colors for lables that don't really mean anything and there is no distinction on the type/context of label.

Here are how it's organized in RIOT:

https://github.com/RIOT-OS/RIOT/labels

here for Zephyr:

https://github.com/zephyrproject-rtos/zephyr/labels

here for RT-Thread:

https://github.com/RT-Thread/rt-thread/labels

I would like to change it to be similar to the examples above:

1. add context for some labels like: "Platform: arm", "Area: Documentation", "Community: help wanted".
   It would be ideal if each label had a context assigned, but I don't know if it's possible.
2. change the color of labels so that labels with the same context have the same color.
3. see what labels are missing (for example, the size of the change)

Does anyone have any objections ? Personally, I like how it's done in RIOT. If you know of any other github projects that have this handled nicely, please link here.

If we have clear and readable labels, we can later automate labeling with https://github.com/actions/labeler and other tools

Verification

• I have verified before submitting the report.

[raiden00pl]

mynewt uses https://github.com/marketplace/actions/pr-size-labeler-action to classify the PR size. This action also helps to limit the size of the PR so that huge changes will have to be split into smaller parts. We can use the size label for further conditions in CI.

[raiden00pl]

Here PR with size labeler:

• github/workflows: add PR size labeler #13542

Here PR that adds specifier to labels:

• github: add specifier to github issue labels #13545

Next steps:

• modify github labels here: https://github.com/apache/nuttx/labels

• initial support for https://github.com/actions/labeler to auto label PRs

• [IDEA] most labels can be assigned automatically, but some labels require a deeper understanding of PR that only the author (or reviewer) has. For example PR type (bug fix, breaking change, enhancement, new feature) must be provided by a human (at least for now, LLM should be able to handle this too).
  For this reason, maybe we should force the PR author to select the "Type:" label. It's minimal amount of work and there's a greater chance that the author will click "breaking change" label when it's required which is commonly avoided now :)

• port all changes to nuttx-apps repo