[ci] Cleanup and order GHA workflows (#4449)

Github currently [doesn't support creating
subfolders](https://github.com/orgs/community/discussions/18055) in
`.github/workflows` folder. PR unifies naming in this folder. The idea
is that all files ideally should have naming
`<stage>-<short_descriptive_name>.yml`. The stage names are taken from
gitlab and needed only for logical division.
Changes in actions:
 - `check-licences` runs on self-hosted runners
- `check-workspace` and `check-markdown` are moved to `checks-quick.yml`
 - `test-linux-stable-int` moved to a new file `tests-linux-stable.yml`
- `fmt-check.yml` file is removed, formatting is checked in
`checks-quick.yml`