In a distant future those might be replaced by core WikimediaUI Base
and this is a sane preparation for it.
Change-Id: I8907c8908f3b775be36b16a6782d7e9719e30c4c
Amending Base10 to slightly darker `#202122` to fulfill WCAG
requirements in connection to Accent50.
Also adding and amending WikimediaUI Base variables where in connection
with the color change.
Bug: T248393
Change-Id: I3b0c1666f7f883908a3778aa9e3fcbf51b57fefe
Introducing stylelint with configuration rules compliant to
Wikimedia CSS Coding Standards 'stylelint-config-wikimedia', nullifying
some for now and making majority pass.
Change-Id: I2c4acee41c9b56d9b00e2a2c5b7ab0ab5de454ce