www-apps/zola: remove

Move ebuild to my personal overlay until zola switch from libsass to
more up-to-date implementation:
* getzola/zola#1535

The problem with sass-rs is that sass-sys build.rs is somewhat not fun
to monkey-patch in order to make QA pass. Sorry about that.

Closes: https://bugs.gentoo.org/830657
Signed-off-by: Alexey Zapparov <[email protected]>