Bump Fedora template to 43 and enhance container installation tooling. Persist DIAGNOSTICS setting and introduce post_progress_to_api() to send lightweight telemetry pings from inside containers (fire-and-forget, enabled when DIAGNOSTICS=yes and RANDOM_UUID set). Harden package management flows: re-detect PKG_MANAGER when commands are missing, add apt mirror fallback logic (apt_update_safe) and more robust apt-cacher proxy parsing. Fix Debian 13 LXC root ownership bug (chown /) and add additional DNS/Git host checks (including api.github.com). Improve downloading and validation of tools.func, add multiple post_progress_to_api hooks to signal progress, and add two new install entrypoints (misc/main/install.func and misc/main/alpine-install.func) that consolidate network checks, OS updates, MOTD/SSH setup and container customization.
Introduces container setup scripts and install scripts for AlmaLinux, CentOS Stream, Devuan, Fedora, Gentoo, openEuler, openSUSE, Rocky Linux, and updates Alpine install script. Adds corresponding JSON metadata files for each distribution in the frontend. These changes enable streamlined LXC container creation and installation for a wide range of Linux distributions.
