Add a "pseudo-task" in nom_build to do the three step process of generating
the golden schema. In the course of this, add support for pseudo-tasks in
general, improve the database directory readme and make nom_build not call
gradlew if there are no tasks.
* End-to-end Datastore to SQL pipeline
Defined InitSqlPipeline that performs end-to-end migration from
a Datastore backup to a SQL database.
Also fixed/refined multiple tests related to this migration.
* Create a nom_build wrapper script
nom_build is a wrapper around ./gradlew. It's purpose is to help us
deal with properties. The main problem that it is trying to solve is
that when properties are specified using -P, we don't get an error if
the property we specify isn't correct. As a result, a user or a build
agent can launch a build with unintended parameters.
nom_build consolidates all of the properties that we define into a
python script where the properties are translated to flags (actual
gradlew flags are also proxied). It also generates the property file
and warns the user if the current properties file is out of sync with
the script and includes documentation on each of the properties.
