Remove development related CLI commands

[merelcht]

Following the research conducted in #1293 it has been decided that the following commands will all be deprecated and removed:

1. kedro jupyter convert
2. kedro activate-nbstripout
3. kedro build-docs
4. kedro build-reqs
5. kedro lint
6. kedro test

Remove all the above commands from Kedro on develop, this also includes updating documentation that mentions any of the above commands.

The template project should still be linted and pytest should run on it, so some of these calls (e.g. in e2e tests) need to be replaced with the underlying calls, e.g. pytest.

This will be released in Kedro 0.19.0

[stichbury]

Just wanted to put a note here so it doesn't get lost. I've updated the docs in advance of the removal of build-docs in #2304 but once we reach the point of removing build-docs we need to revisit those docs and also do the following:

• Remove the code for build-docs (obvious)
• Remove the docs dependencies in setup.py:

"docs": [
            "docutils<0.18.0",
            "sphinx~=3.4.3",
            "sphinx_rtd_theme==0.5.1",
            "nbsphinx==0.8.1",
            "nbstripout~=0.4",
            "sphinx-autodoc-typehints==1.11.1",
            "sphinx_copybutton==0.3.1",
            "ipykernel>=5.3, <7.0",
            "Jinja2<3.1.0",
            "myst-parser~=0.17.2",
        ]

• Update the project template/starter to remove the docs/source subfolder so there's no existing conf.py and index.rst to confuse things (then we can update these docs again).
• Potentially, add basic documentation into the project template as to how to create docs (put a markdown folder in the /docs folder maybe) that echoes this advice on using Sphinx.

[noklam]

Closed by #3065