Make dependencies_v2 the default for Cassandra

[yurishkuro]

After #1328 is released:

• make dependencies_v2 the default for Cassandra
• make v002 schema the default
• fix documentation

[pavolloffay]

I have marked * make v002 schema the default as done - the create schema script uses the new schema by default.

The make dependencies_v2 the default for Cassandra can be also considered done - Jaeger components uses v2 if dependencies_v2 table is present.

So is there anything apart from docs what should be done? What docs should be updated? How to migrate to v2?

cc @black-adder

[pavolloffay]

I am closing this:

• V2 schema is used by default in create schema script and docker image
• migrations steps are in changelog
• jaeger binaries automatically regognizes if v2 schema is initialized

[pavolloffay]

Note that Cassandra create schema script creates keyspace jaeger_v1_${datacenter} (note V1 in name) for V1 and V2.