ogt_vox: add type-based memory alignment within the internal sub allocator

[jpaver]

• attempted fix for https://github.com/jpaver/opengametools/issues/62.
• we now use a new _vox_suballoc_array type that internally aligns base offset to the size of the type by default (in cases where alignment matters, I'd expect the struct to be padded to the natural alignment and for all members to have appropriate alignment padding for them too)
• this still relies upon a reasonable alignment from _vox_malloc, which should either be guaranteed to be 8 or 16 in most 64-bit platforms

@mgerhardy, PTAL and confirm this fixes your ASAN testing issue. Thanks!

[mgerhardy]

Thanks a lot for the patch - applied it to vengi - if this pipeline run is successful, this can get merged.