Remove customizableProperties from `android.ModuleBase`

- customizableProperties was being used to access all properties,
i.e. basically `GetProperties()`

- generalProperties was a subset of properties,
i.e. `initArchModule()` would only add new arch-specific properties
to `customizableProperties` (and `archProperties`) but not `generalProperties`

This PR sets generalProperties to contain all properties,
which then makes customizableProperties redundant.
And in arch.go, any iteration is done via `archProperties` instead.

Bug: 206961391
Test: m nothing and diff the ninja files
Change-Id: Ieb72b31c0a447fcbf34c92a04f002d7b9d777a86