Tagging/Manifests/Tests/Wiki changes

[mathbunnyru]

@consideRatio @yuvipanda @manics

I completely redesigned how tagging/manifests and tests directories look like, made everything more modular and easy to read.

This issue is to let you know of large changes I implemented in the past fews days:

• Better tagging directory structure (Better tagging directory structure #2228)
• Better testing directory structure (Better tests directory structure #2231)
• Also did the similar thing in cookiecutter repo
• Add tagging config to pass params easier (Add tagging config to pass params easier #2234)
• New https://jupyter-docker-stacks.readthedocs.io/en/latest/maintaining/tagging.html page
• A bunch of changes to properly update wiki in forks (if someone needs it and also removes hardcode)
• MarkdownPiece class ([FAST_BUILD] Add MarkdownPiece class to make manifest pieces better structured #2238)
• Refactor tagging: create functions, better logs and names, textwrap.dedent ([FAST_BUILD] Refactor tagging: create functions, better logs and names, textwrap.d… #2239)
• Refactor wiki: create functions, better logs and names ([FAST_BUILD] Refactor wiki: create functions, better logs and names #2242)

I suggest looking at tagging, tests and wiki dirs to see how it looks like now.

If you have any questions/suggestions, it would be highly appreciated.

I will close this issue in a week or so.