Switch from ASDF & various too complex custom Bash script to all-in on Flox.dev

[vorburger]

#1227 follow-up... ToDo:

• Isolate fully, with env -i (is this actually possible?), or like build: Explore running build & test scripts under an isolated Flox.dev PATH #1235; see (How to) Create isolted environments flox/flox#2447 (later contribute Document workaround for fully isolated flox environments flox/floxdocs#90). Or... learn more about somehow directly running build & test scripts under nix {shell|develop} --pure? (And then use https://github.com/nixbuild/nix-quick-install-action or https://github.com/cachix/install-nix-action from https://nix.dev/guides/recipes/continuous-integration-github-actions, or https://github.com/DeterminateSystems/nix-installer-action?? See this.)
• GitHub Action caching? See Document if install-flox-action does any caching by itself, or how to use it other actions for caching flox/install-flox-action#107.
• Bazelisk via Flox.dev
• Bun with Flox instead of ASDF: Pending Update Request: bun 1.2.5 → 1.2.7 NixOS/nixpkgs#394639
• protoc with Flox instead of ASDF: build: Install protoc via Flox from Nix instead of ASDF #1242
• Remove ASDF entirely: .tools-versions, tools/asdf/, GitHub Action
• IPFS Daemon service (?)
• Dev container https://flox.dev/docs/tutorials/sharing-environments/#always-using-the-same-environment-across-multiple-devices and then comment on Tutorial on using Flox in cloud development environments flox/floxdocs#36
• How does one fix the nixpkg version?!
• Research dependabot or renovate or custom for https://github.com/enola-dev/enola/commits/main/.tool-versions - keep and mix, or replace entirely with TOML? Or does https://flox.dev/docs/reference/command-reference/flox-upgrade/ actually do that? See also Describe how to use CI to automatically update environments flox/floxdocs#69.
• Disable now removed ASDF et al actions from https://github.com/enola-dev/enola/settings/actions
• https://github.com/vorburger/Notes/blob/master/Reference/flox.md#activation improvements re. https://github.com/vorburger/vorburger-dotfiles-bin-etc/blob/main/dotfiles/fish/functions/flox.fish, and blog about it? (Or just use switch to using direnv, instead?)

Possible alternative, if for some reason this doesn't work out (now, or in the future):

• https://devenv.sh
• https://www.jetify.com/devbox
• https://nix.dev "directly"
• See https://github.com/vorburger/LearningLinux/blob/develop/nix/README.md
• https://mise.jdx.dev: Not Nix (much less packages), but has e.g. nice https://mise.jdx.dev/ide-integration.html#ide-plugins