Remove support from profiles and mkarchiso

Remove `` scripts. They were deprecated with v47.

Remove all `` related functionality (i.e. `command_pkglist()`, `command_iso()`, `command_prepare()`,
`command_install()`, `command_init()`, `command_run()`).

Rename `command_build_profile()` to `_build_profile()` to be more in line with the style of the other function naming.

Change `_show_config()` to only print info about the profile and make no more use of parameters.

Remove all help output related to legacy `` commands.

Fixes #51
1 job for master in 29 seconds (queued for 3 seconds)