General docs improvements for v3.0 (#2280)

* Split the docs into sections

* Split the options page into two pages - so the reference is more clean

* Reorder/Tidy up this 'deliver' page to make auto-deploy more obvious

* Fix up some links

* Merge the platform docs into a single page to clean up the navbar.

* Split the setup page to make a page dedicated to CI setup

* Move general platform-specific information into the platforms page

* Tidy up the platforms page

* Remove some redundancy in the cpp/platforms docs

* Clarify this section

* Move another FAQ entry to the platforms page

* Remove some out-of-date entries from the FAQ

* A few corrections to the options page

* Fix some broken links

* Improve the Docker references

* Update bump version filename

* Improve options TOC information density

* whitespace

Co-authored-by: Henry Schreiner <HenrySchreinerIII@gmail.com>

* Convert the normal test invocation to `pytest ./tests`, not placeholder

---------

Co-authored-by: Henry Schreiner <HenrySchreinerIII@gmail.com>

bin/bump_version.py

@@ -23,6 +23,7 @@ config = [
     ("docs/faq.md", "cibuildwheel=={}"),
     ("docs/faq.md", "cibuildwheel@v{}"),
     ("docs/setup.md", "cibuildwheel=={}"),
+    ("docs/ci-services.md", "cibuildwheel=={}"),
     ("examples/*", "cibuildwheel=={}"),
     ("examples/*", "cibuildwheel@v{}"),
 ]