cmake: add ggml find package (#11369)

cmake: add ggml find package (#11369)

* Add initial ggml cmake package

* Add build numbers to ggml find-package

* Expand variables with GGML_ prefix

* Guard against adding to cache variable twice

* Add git to msys2 workflow

* Handle ggml-cpu-* variants

* Link ggml/ggml-base libraries to their targets

* Replace main-cmake-pkg with simple-cmake-pkg

* Interface features require c_std_90

* Fix typo

* Removed unnecessary bracket from status message

* Update examples/simple-cmake-pkg/README.md

Co-authored-by: Georgi Gerganov <redacted>
* Update examples/simple-cmake-pkg/README.md

Co-authored-by: Georgi Gerganov <redacted>
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Co-authored-by: Georgi Gerganov <redacted>