[FEATURE] Add .inline property to includeCSS/includeCSSLibs

If .inline is set, the contents of the css-file is inlined
using <style>-tags.

.inline implies .excludeFromConcatenation.
.import takes precedence over .inline.
The other properties of includeCSS still work if .inline is set.

Resolves: #81223
Releases: master
Change-Id: Id08fb0ce201d6992f68a1ac3f9d7735483cee3d7
Reviewed-on: https://review.typo3.org/53077


Reviewed-by: Henning Liebe <h.liebe@neusta.de>
Tested-by: Henning Liebe <h.liebe@neusta.de>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Susanne Moog <susanne.moog@typo3.org>
Tested-by: Susanne Moog <susanne.moog@typo3.org>