ci: disable doc deploy until hosting is configured
Add MkDocs build manifest

This is a simple manifest that spins up an Arch VM, installs Material
for MkDocs [1], builds the site, then pushes it to a web server. The
port, user, server IP address, and webroot path are specified using
environment variables.

[1]: https://squidfunk.github.io/mkdocs-material/
[2]: https://www.mkdocs.org/
delete index of specs because it's unnecessary
modify page titles

- Index page will show up under the site name (Arbor Chat) and having
  the title of the page the same as the site is a bit repetitive.
- Remove "Specification" from the titles of forest and sprout docs for
  the same reason
- Remove "Arbor" from technical overview for the same
reorganise and merge guides

- The Getting Started and Hosting an Arbor relay guides have been moved
  to the guide/ directory
- getting-started.md now includes a note about wisteria being deprecated
  as well as the usage guide at the bottom in case someone is interested
  in picking it up
- getting-started-cli.md has been deleted (merged with main)
add support for new vale

Something in a recent update broke one of our rules and that has been
corrected in this commit.
add contributing doc and mention vale linting
doc: add summary top paragraph to hosting doc
doc: document how to set up an arbor relay
docs: fix markdown rendering of button list
Add custom mkdoc theme
fix: update branch names

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
update getting started guide

I went through the guide and updated portions to reflect UI changes and
make some of the process clearer. I also fixed the headings and ran the
file through Vale, correcting some of the errors and warnings.
integrate vale

This massive patch attemps to standardise out documentation. For those
unfamiliar with it, Vale is "a syntax-aware linter for prose built with
speed and extensibility in mind" [1]. I built on Vale's
implementation [2] of Google's style guide [3] with specifics for Arbor
and the vocabulary we've started using.

[1]: https://github.com/errata-ai/vale
[2]: https://github.com/errata-ai/Google
[3]: https://developers.google.com/style/

I didn't modify any of the docs that are already written so some of them
will have a ton of errors. Once Arbor's style has been reviewed and a
bit more polished, I'll go through and start implementing the
recommended changes. To that end, install Vale [1], run it on a few
files, and see what the output says. Feedback is welcome.

[1]: https://errata-ai.gitbook.io/vale/getting-started/installation
Add Sprig to project list
docs: fix typo
add new diagrams and update docs

I added the new diagrams and updated the docs to include them along with
an explanation of what's going on for the simpler overview.

I included the graphml files so they can be imported and edited/improve
later on but I don't know how they'll work in other programs; I created
them in yEd: yworks.com/products/yed

The dark diagrams have transparent backgrounds so they should be
suitable for any shade and the light diagrams are simply white. SVGs are
including for editing colors and exporting at various sizes.
move wisteria guide to separate doc
replace wisteria guide with one for sprig
make spec links relative

The previous links would lead to sourcehut's root and 404 but these should
lead to the correct locations.
Remove outdated implementation links.