docs: Update Starter Pack

[rkratky]

• Starter Pack update
• Content update

[rkratky]

@asanvaq, apologies for the delay. This is now ready for review & merging.

[cjdcordeiro]

Thanks for the update. I'm afraid we can't merge this as is. Here are a few notes:

1. this is applying changes way beyond the scope of the starter pack (51 files changed 🤯 )
2. some of these changes are actually touching the contents of the docs, including removing things like the checklist of the "how to slice a package" guide, or rephrasing contents of the security reference
3. it also changes significantly the meta tags of the resulting docs (conf.py), which is something that should be reviewed in separate
4. it is removing and adding CI workflows. This would've been kind of acceptable if the changes were associated with the update of the starter pack, but some don't seem to be. E.g. the cla-check is needed, but unrelated to this PR; the markdown-style-checks and check-removed-urls add useful jobs, but seem like a boilerplate copy of a bunch of steps that may be equal for many other doc pages - thus these should instead be using reusable workflows (like the automatic-doc-checks instead of duplicating steps which will soon be outdated and requiring constant maintenance