meson: move build definitions of software_generic to libevas

meson: move build definitions of software_generic to libevas

Summary:
with this we don't have any static module anymore in the engine
directory. This means either *all* modules in the enignes directory are
static OR shared. There is no mixture anymore. This is a requirement for
the directory to be build whenever we want it to be build.
Depends on D8667

Reviewers: zmike, stefan_schmidt, cedric, vtorri

Reviewed By: zmike

Subscribers: #reviewers, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D8668

Change-Id: I973c4366b888d1d452b8b0e25340b6fc6dd5a5b5