This patch handles both implicit and explicit template instantiations of
template class static member variables.

This change introduces the #cir.global_view attribute and adds support
for using that attribute to handle initializing a global variable with
the address of another global variable.

This does not yet include support for the optional list of indices to
get an offset from the base address. Those will be added in a follow-up
patch.

This adds support for initializing the vptr member of a dynamic class in
the constructor of that class.

This does not include support for lowering the
`cir.vtable.address_point` operation to the LLVM dialect. That handling
will be added in a follow-up patch.

This PR adds a support for file scope assembly in CIR.

This fixes a number of warnings in release builds due to variables that
were only being used in asserts. Some of these variables will later be
used in non-debug code, but for now they are unused in release builds.

This implements support for structured bindings on a function scope
level. It does not add support for global structured bindings.

This patch adds or completes support for a couple of top level
declaration types that don't emit any code: Most notably these include
Concepts, static_assert and type aliases.

This fairly simple addition enables codegen for C++ conversion operators