cc: add min_sdk_version prop

min_sdk_version is the minimum version of the sdk that the compiled
artifacts will run against.

For example, when a module is used by two APEXes and their
min_sdk_versions are set to 29 and 30, then the module should support
both versions even if it is compiled against 30. Therefore,
min_sdk_version of the module needs to be set 29 in that case. In
general, this is set as the minimum value of min_sdk_vesions of APEXes.

For now, there's no build-time checks about this prop even if the prop
is set.

Bug: 145796956
Bug: 152655956
Bug: 153333044
Test: m nothing
Change-Id: I072ad8c317d2615e8b08e4e7ea2db8e7955b4b12