Rework how QP bounds are passed, AVC encoder

Pass via an (variable length) set of settings for picture types
instead of the fixed I/P/B types. Also makes it possible to
pass a max without also passing a min.
This is for the AVC software encoder; other codecs will be modified
accordingly.

Bug: 181830609
Test: vq testing, ALOG
Change-Id: I9086c0d83e625a7a815ce2c104352fdac165b927