Group injected tiles together based on package name.

During grouping, tiles are sorted based on package name, and their own
priority value. However if the package is Settings itself, the ordering
is not changed.

Before sort: [pkg1, 100], [pgk2, 120], [pkg1, 130]
After sort: [pkg1, 1], [pkg1, 2], [pkg2,3]

This is necessary to make sure settings app have the overall control of
ordering of all dynamic tiles. When each app define their priority, they
don't have access to the global vision of what other settings are on
screen so it's possible different app define conflicting orderings.
Settings app is the only reasonable place to rank them properly.

Bug: 32827787
Test: RunSettingsLibRoboTests
Change-Id: I38de55530e61da9de7532ef6a7ee97ef89aca9d9