[dartdev/analyzer/linter] Consider adding a command to add a linter rule

[parlough]

I've seen this mentioned a few times before but I couldn't find a dedicated issue for it here. As we work to improve the linter rule documentation in the future (related dart-lang/site-www#4498), it would be nice if we could just give users a command they can copy with a button and run to add or remove a linter rule. dart pub add has been an extremely useful command in documentation with a similar goal.

The command could be part of a new dart linter or dart analyzer tool, or just added as a subcommand to dart analyze. It would probably be fine as a hidden command from --help unless other functionality is added, as I imagine most use cases will be from documentation and blog posts.

1. Check if the lint exists, error if it doesn't
2. Check if the lint is already applied (within the same file, not included ones), if it is, tell the user that
3. Check if the lint is incompatible with any applied ones, error if it is and inform the user of the incompatibility
4. Add the lint to the list (preferably sorted)

[pq]

/fyi @jacob314

[parlough]

I'm beginning to think a solution like dart-lang/pub#4052 might be more sustainable as it would be easier to evolve outside the normal guarantees of the SDK.