minui: Move to Soong.

Note that although libminui says "shared_libs" in Android.bp file,
`recovery` binary will still statically link the libs, until we drop the
`LOCAL_FORCE_STATIC_EXECUTABLE := true` flag from `recovery` module.

Bug: 110380063
Test: `mmma -j bootable/recovery` with aosp_taimen-userdebug
Test: Boot into recovery and `Run graphics test`.
Change-Id: I48785d161dfe52eb01667e938d9c3f0a497b61a2