Update documentation with Dockerfile linters and the rest

[phracek]

meta-test-family does not container list of linters which MTF supports.

Update it as soon as possible.

• [x] https://github.com/fedora-modularity/meta-test-family/blob/devel/moduleframework/tools/dockerlint.py
• [x] https://github.com/fedora-modularity/meta-test-family/blob/devel/moduleframework/tools/helpmd_lint.py
• [x] https://github.com/fedora-modularity/meta-test-family/blob/devel/moduleframework/tools/modulelint.py

[phracek]

Closing. PR is merged.