Migrate existing terminal implementations to new architecture from #505

[DonnerWolfBach]

In #505 a new "architecture" for how terminal should be supported/implemented was defined. However, not all existing implementations where migrated to this new style yet. This issue will contain a list of the missing and already migrated terminals.

Linux:

• kde-konsole
• gnome terminal
• guake
• termite

Mac:

• apple terminal (the default terminal)(#568 )
• iterm

Windows:

• mintty
• powershell (in progress by @DonnerWolfBach #711)
• windows_terminal (in progress by @DonnerWolfBach #711)
• command processor
• wsl/ubuntu

The implementation of kde-konsole serves as a reference of how it should/could be done.

[DonnerWolfBach]

@fidgetingbits should we remove termite from the list and add alacritty instead?

[fidgetingbits]

may as well just have both termite and alacritty I think, just because it's deprecated doesn't mean people won't use it since it's still stable, and no real harm in keeping it imo.

[DonnerWolfBach]

For everybody in need of an explanation of the new "terminal architecture", here the summary from here: generic_terminal.talon lists some commands that should be possible in every terminal, like lisa (list directories). generic_windows_shell and generic_unix_shell.py provide the implementations for these commands (there are major enough differences between windows shells and unixoid shells). Everything else, like tab support, activation of specific commands sets(like git,anaconda,kubectl) is done in the .talon and .py files for the specific terminals.

[rntz]

Is this done yet? What's its current state if not?

[DonnerWolfBach]

@rntz Still work in progress, but powershell and windows powershell is finished and waits to be merged: #711