HTML and Markdown need to be separated by an empty line to co-exist, otherwise the Markdown isn't parsed correctly.

* Reorganize readme, add gif

1. Details in 'Getting Pyenv' and 'Setup for your shell' are collapsed. User can expand relevant
   sections depending on their platform and shell.

2. 'How It Works' and 'Advanced Configuration' are moved to the bottom of the README.md
   just before 'Contributing' section at the end.

3. Added a GIF in the 'Usage' section to showcase
   - Listing python versions available for install.
   - Installing a specific python version.
   - Listing installed python versions.
   - Switching to another python version for a directory.
   - Testing by moving terminal into the directory and moving back.

* Update GIF to show prefix resolution

* Collapse upgrade notes

* Cross-mention Linux and MacOS instlalation scenarios

---------

Co-authored-by: Ivan Pozdeev <vano@mail.mipt.ru>

Add Anaconda3-2024.10-1

Co-authored-by: binbjz <zhaobin@avenir.hk>

Since 3.13, CPython is provided in 2 flavors: regular and
free-threaded, with the 't' suffix.

An incomplete prefix ending with '[0-9]t'
resolves only among versions that also end with '[0-9]t'

`::set-output` is deprecated as per https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

Closes #3069

changed OpenSSL URLs to permalinks so that they keep working

Fixes use of version specifiers like `python-3.12`, which:
- have an explicit `python-` prefix
- are using a major version alias that has to be resolved
  to an exact version.

Also simplified the conditional for the already
working case, since it had two branches that were virtually identical.

N.B.: 7.3.17 frops Python 3.9 support as well as s390x platform
releases. See: https://pypy.org/posts/2024/08/pypy-v7317-release.html

Co-authored-by: binbjz <binbjz@skiff.com>

The directory /usr/etc is an optional directory and used by
Fedora, RHEL 9, and openSUSE. The purpose of /usr/etc is to store
distribution-provided configuration files that can be overridden
by user-modified files in /etc.

/usr/etc is not in FHS. However, as Torsten stated in his comment
(https://github.com/thkukuk/atomic-updates_and_etc/issues/2#issuecomment-524848666)
"[FHS] is currently nearly as dead as LSB, we can only ignore it
if we don't want to stop and kill all innovation."

pyenv-latest: replace -q with -b and -f, document as internal

Drop the failing test in favor of a better-written test
that also tests the same

Easy syncing with Rbenv is not as important now

More tailored for the emergent internal use cases

[Fig](https://fig.io) has been sunlit for new users, with access being removed in September