Update OpenXRAPI memory management

[devloglogan]

It was mentioned here that OpenXRAPI could use some updates to its memory management. I've updated it to use Vector/LocalVector where possible!

[dsnopek]

Thanks! This will be a very welcome change :-)

I haven't tested with this PR, but reading through the diff, it looks good to me

However, I think there may be a couple more places where we could use Vector/LocalVector, for example, in OpenXRAPI::RenderState with the views. Also, in openxr_opengl_extension.cpp and openxr_vulkan_extension.cpp.

Any reason why you skipped those? It would be nice to knock them all out at once.

[devloglogan]

@dsnopek Thanks for pointing those out, I will take a look and update them soon!

[devloglogan]

@dsnopek Alright, I believe I've updated the other instances you were referring to.

[m4gr3d]

The code change looks good!

[devloglogan]

@m4gr3d applied your error nit and discovered I could remove the intermediary pointers to the render_state vectors, so I did that too.

[dsnopek]

Looks good! I only have some nitpicks about doing unnecessary if-statements before .clear()ing the vectors.

I also did a quick smoke test with Quest 3 and everything seems to be working fine

[devloglogan]

@dsnopek addressed your comments, thanks!

[dsnopek]

Thanks!

[akien-mga]

Thanks!