add proper license information to all themes

Merged Christoph Cullmann requested to merge work/theme_license_data into master

for older themes, digged out of the git history of this/ktexteditor/kate repos for newer themes just taken from the last merge requests + commits referenced license of the original authors for imported themes

add unit test that ensures all stuff is properly license

  • enforce MIT as SPDX identifer
  • enforce some copyright array elements are there as SPDX identifier

it is a bit 'relaxed' as we can't require contact addresses

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