metal : refactor kernel loading code (llama/4794)

metal : refactor kernel loading code (llama/4794)

* metal : detect more GPU families

* metal : refactor kernel loading

* metal : set kernel family requirements

* metal : fix kernel init + fix compile options

* metal : take into account simdgroup reduction support

* metal : print only skipped kernels

* metal : fix check for simdgroup reduction support

* metal : check for Metal 3

* metal : free allocations

* metal : normalize encoder:setComputePipelineStatus calls

ggml-ci

* metal : fix Metal3 family check

ggml-ci

* metal : check for simdgroup matrix mul. feature

ggml-ci