This includes renaming the billing classes to match the SQL table names,
as well as splitting them out into their own separate top-level classes.
The rest of the changes are mostly renaming variables and comments etc.
We now use `BillingBase` as the name of the common billing superclass,
because one-time events are called BillingEvents
* Rename ContactResource -> Contact
This is a follow-up to PR #1725 and #1733. Now all EPP resource entity class
names have been rationalized to match with their SQL table names.
* Rename DomainBase -> Domain
This was a long time coming, but we couldn't do it until we left Datastore, as
the Java class name has to match the Datastore entity name.
Subsequent PRs will rename ContactResource to Contact and HostResource to Host,
so that everything matches the SQL table names (and is shorter!).
* Merge branch 'master' into rename-domainbase
Added overviews for EPP resources, billing events, history entries.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=136732236
The section headers can be re-added later along with their actual content.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=136349771
This changes everything with external visibility beyond the codebase
(i.e. the name of the compiled binary and the documentation that refers
to it). It does not change a lot of things internal to the codebase,
i.e. the "RegistryTool" class didn't change its name. We can rename that
in a subsequent CL if we want to.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=135022087