Converts lingering panic alert calls over to the fmt-capable ones.

Fixes https://bugs.dolphin-emu.org/issues/12245.

I considered making a change to DolphinQt instead of
the core, but then additional effort would've been
required to add the same fix to the Android GUI once
we start using the new config system there.

These are only ever used with ShaderCode instances and nothing else.
Given that, we can convert these helper functions to expect that type of
object as an argument and remove the need for templates, improving
compiler throughput a marginal amount, as the template instantiation
process doesn't need to be performed.

We can also move the definitions of these functions into the cpp file,
which allows us to remove a few inclusions from the ShaderGenCommon
header. This uncovered a few instances of indirect inclusions being
relied upon in other source files.

One other benefit is this allows changes to be made to the definitions
of the functions without needing to recompile all translation units that
make use of these functions, making change testing a little quicker.

Moving the definitions into the cpp file also allows us to completely
hide DefineOutputMember() from external view, given it's only ever used
inside of GenerateVSOutputMembers().

glReadPixels() with depth formats is not supported.

Should fix broken EFB access on GLES.

"Cache data" can be used to assist a driver with creating pipelines by
using previously-compiled shader ISA.

Qt/HacksWidget: Fix backend feature support checks

Prevents attempting to create invalid MSAA configurations, for example.

D3D11 doesn't support partial copies of depth buffers via
CopySubResource(), so we need to use a different path for the EFB cache.