Add new API to performing grouping and ordering of bindings.

This will allow apps to better manage many isolated processes,
telling the system how they are grouped together (so should be
managed as one related entity within the LRU cache) and fine-tune
the ordering within that group.

The API is not yet tested...  though in theory it is implemented.
But the implementation done for that also fixes a *lot* of problems
with activity LRU management that, even without groups, should
make the ordering of processes in the LRU list much more consistently
match how recently the user has interacted with it.

Also clean up some of the new dumpsys output in the activity manager:
move the new sections to before the process output (so it is still
easy to see the process state at the end of the output), and add and
document the command line options for controlling them.  And add a
new "lru" section that gives a clear view of what is going on with
the raw LRU list.

An upcoming change will add tests for the new grouping functionality,
and probably some fixes resulting from that.

Test: atest CtsAppTestCases:ServiceTest
Bug: 111434506
Change-Id: I1f6b6b9de66ccde1573e1a0e9615e8c5f8e6c0d7