PgServerTool 0.1 installer

Start it:   ./pgst-installer
It installs PgServerTool on this computer (Ubuntu 24.04 LTS or a distribution built on it, such as
Linux Mint) or on such a server over SSH, from any Linux desktop (Linux Mint, Ubuntu, Omarchy/Arch).

Without a desktop:
  PGST_ADMIN_PASSWORD='...' ./pgst-installer --cli --ssh USER@HOST[:PORT] --panel-host panel.example.org --admin NAME
  ./pgst-installer --help
