Interactive mode for CLI

Suggestion to add an interactive/shell/prompt mode for the installer's CLI.

This means the end-user invokes the installer or maintenance tool with the keyword to starts the interactive mode. The user is given a prompt to run any of the existing commands until explicitly exited. This means single commands could be run multiple times, or different commands chained:

$ ./installer.run interactive
> check-updates             -> updates available...
> update                    -> success!
> exit

$ ./installer.run interactive
> search qt                 -> too broad output, let's narrow the search..
> search qt.qt6.620         -> output: qt.qt6.620.gcc_64,... etc.
> install qt.qt6.620.gcc_64 -> success!
> exit

$ ./installer.run interactive
> list                      -> output: qt.qt6.620.gcc_64,... etc.
> remove qt.qt6.620.gcc_64  -> success!
> exit

This would potentially speed-up the CLI usage, if it would be possible to avoid fetching, extracting and evaluating metadata again for every command.