As the library avoids branching as much as possible there is no reason
to share functions in the binary between the SVE2 and SME/SME2 paths.
That kind of sharing is made possible by the __arm_streaming_compatible
attribute.
In addition, functions using SME2 instructions must be attributed with
the __arm_streaming (or __arm_locally_streaming) keyword.

Specify CMake's 'Release' build type on CI for the coverage runs to not
to cause coverage loss for asserts, as in most of the cases those assert
paths cannot be driven through the API tests.

Update the list of long vector tests for the local coverage script.

* Make it work with SME2 sources.
* Print output to disasm.txt as well.
* Demangle C++ symbols.

So far all SME2 implementations only used the SME feature set, so it
makes sense to rename it to just SME and compile it for the SME
extension. That way future implementations using SME2 features can be
distinguished.

Changes related to filenames are part of a separate commit.

Add an example for extracting one operation from KleidiCV as well.

As it is known at compilation time whether the streaming or
non-streaming variants should be used.

In some environments it causes issues if the non-streaming routines
are called from streaming-compatible functions. (The correct behaviour
would be that the compiler automatically links to the streaming
variants in such a case.)

Gaussian Blur 15x15 kernels always use the custom sigma variant,
with much better performance and near the same accuracy.
Custom Sigma kernels are uniformized and simplified using
std::reference_wrapper in the SVE variant.

Update documentation with oldest supported GCC version as well.

Benchmarks added for Gaussian blur 21x21 and Medan blur benchmarks are
extended.