Add Updater class and remove UpdaterInfo

The UpdaterInfo class is merely a collection of pointers and POD types.
We can replace it with a Updater class that has the ownership of the
resources. This also makes this class extensible as we plan to add more
functionality in the host simulator.

Bug: 131911365
Test: unit tests pass, run an update on cuttlefish and check last_install
Change-Id: I07ca5963bbee8ae3cb85ccc184464910aa73d4e4