5.0 beta, everything that touches resources needs MRs

[Wolthera]

Hi everyone,

Today it became clear that there's a number of edge cases in the
resource management, in particular with regards to embedding
resources.

To ensure everyone is on the same page, we've decided that all code
that touches the resources, from anyone, needs to have MRs made. I
personally would also like everyone to make unittests for resources,
so we can communicate the particular edge cases more clearly.

Because of the sensitivity of the remaining resource system issues, I
will revert everything that touches resources that I cannot find a
corresponding accepted MR for, regardless of how many crashes it fixes
;)

Thanks in advance,
-- 
Wolthera