Rewrite install script

[arcticicestudio]

Fixes #12
Fixes #6
Fixes #3

Prehistory

The profile script is currently not usable due to a undocumented behavior of dconf resulting in whether overriden profiles or error messages. The logic of the script worked previously, but the dconf or gsettings API changed breaking the script (forks of terminal.sexy) which's logic is used by almost all GNOME Terminal theme projects.

I've reported #789056 to the official GNOME bug tracker for the dconf component which got closed with the following reason:

This is simply an error in your script: you're using dconf to read keys that have never been written to. You need to use the gsettings tool instead, which takes into account the schema so it can return the default value in that case.

I tried to find the documentation where this behavior of dconf is described, but it seems like this knowledge is only documented in the code itself or internal developer documents.

Description

Since the script was never really optimized I decided to rewrite it to fix issues like #12 and #3 and implement the following additional features:

• Profile Handling - the script should be able to detect available profiles and
  • clone the default profile if no specific profile has been specified - The script must be able to get the UUID of the default profile and clone it
  • install the theme for a specific profile - the user should be able to pass the name of the profile the theme should be installed to
  • handle already existing Nord profiles and compare the version - if the Nord GNOME Terminal theme Nord profile already exists and the script version less than the installed version the user should be able to confirm whether to override the theme of abort the installation, otherwise the profile should
    • be updated if the script version is greater than the installed version
    • be reinstalled if the installed version is equal to the script version
• Log Level - the script should provide a option to allow the user to define the log level where the available levels should be
  • 0 - ERROR
  • 1 - WARNING
  • 2 - SUCCESS (default)
  • 3 - INFO
  • 4 - DEBUG
• Dependency Management - the script should be able to validate all required dependencies to ensure the script can run on the executive environment which includes
  • dconf (dconf)
  • expr (coreutils)
  • gsettings (glib2)
  • uuidgen (util-linux)