multimedia/gstreamer1-editing-services: update to 1.16.3 and use meson

• Switch to meson for the build, re-enabling Python 3.10+ compat.
• Add gstreamer1-validate support and LIB_DEPENDS.
• Drop pycache from install and Perl5 and autotools from requisites.

Reported by: VVD@unislabs.com (IRC)
Discussed with: vishwin@, diizzy@
PR: 264611
Approved by: maintainer timeout (multimedia@, 19 d)