Revisit the project linting scope

[somaritane]

According to the discussion in #774 (comment), not all project paths are covered by our linting workflows/tasks.

[kuritka]

fount this:

• Add support for multiple subdirs each with their own go.mod golangci/golangci-lint#828

Once go.mod is added to subfolder, it is skipped by local linter.

[ytsarev]

linting was tweaked multiple times, assuming this one solved