Add zsh completions (compdef) for konsole

Note: it uses the new variable KDE_INSTALL_ZSHAUTOCOMPLETEDIR, which was added in ECM 5.101.

Read more: frameworks/extra-cmake-modules!310 (merged)

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This actually quite a bad job not so bad:

• Completions for konsoleprofile do not really stack with a separator ';'
• Property types other than bool & int are not supported (at least colors and fonts could be implemented, I think?)
• Couldn't find a way to enforce that -e options is the last, and only complete with _cmdambivalent after it: it either ignores me, or dived into recursion hell with _tags:comptags:67: nesting level too deep errors.