This commit is the forward port of renaming the type for esusers to file. There is no
backwards compatibility maintained here. Additionally, a few other renames and
cleanups have been made:
* `esusers` commands is now `users`
* org.elasticsearch.shield.authc.esusers -> org.elasticsearch.shield.authc.file
* Validation.ESUsers -> Validation.Users
* ESUsersTool -> UsersTool
* ESUsersToolTests -> UsersToolTests
* ESNativeUsersStore -> NativeUsersStore
* ESNativeRolesStore -> NativeRolesStore.
* org.elasticsearch.shield.authz.esnative collapsed to org.elasticsearch.shield.authz.store
* ESNativeTests -> NativeRealmIntegTests
Closeselastic/elasticsearch#1793
Original commit: elastic/x-pack-elasticsearch@d2a0c136f3
jaymode