docs(reference): migrate from kteam-docs

[AnneCYH]

Migrate content from reference section in kteam-docs.

[gagath]

The HWE kernels page looks a lot like a howto and does not define what a HWE kernel is in its first paragraph. I think this should be reworked and does not quite fit into a reference in its current form.

[AnneCYH]

hi @gagath ,

This is one of those things where it seemed 'extravagant' at the point of writing to split out the "Installing" and "Reporting bugs" section to standalone how-tos.
While the "Support lifecycle" was intended to serve as a reference on the release dates.
And the part before the diagram is an explanation of sorts. Again it seemed excessive to split everything out at the point of writing.

I agree it definitely can be reworked especially for the how-to portions. I think it should just be a how-to on installing kernels and include all the relevant variants (e.g. RT kernel approach is different also).