Introduce dynamic resolution of git build hashes by fetching the upstream
installer script and parsing the values, with fallbacks to built-in defaults
and support for user overrides via environment variables.
Add fetch_gitbuilds() to retrieve and parse hashes, and resolve_artifacts()
to populate artifact filenames and URLs based on resolved hashes.
Call these functions early in main() to ensure up-to-date artifacts before
downloading. Skip upstream fetch if DONOTDOWNLOAD=1 is set.
Introduces a community-maintained installer script that supports multiple Linux distributions including Debian, Arch, Fedora, and openSUSE. Includes README with usage instructions, supported distros, and disclaimer. The script handles dependency installation, downloads, verification, and setup of SDRconnect and RigControl.
