Refactor InputDataStore to be able to store any type of data

Making InputDataStore parameterized so it can be used to store
multiple types of data. This will be used to migrate all the data
stored in PersistentDataStore to this new per-user, backup and
restore compatible InputDataStore

Bug: 326193017
Test: atest InputTests
Flag: EXEMPT PURE_REFACTOR
Change-Id: Ida754af6486b8cbd44e34dd9108c80490137aa7b