3rd alpha for 4.x

Includes fix for bootstrap issue

• Fix handling of cluster startup.

Previously we would provide the local node as a seed even if
auto_bootstrap was set to true, which meant that when doubling we could
potentially stream no data. Providing the local node as a seed was added
to work around the (imo buggy) behaviour introduced in CASSANDRA-10134
where the shadow round fails unless the node is a seed which even if
autobootstrap was turned off.

• Test for InstanceIdentity properly handling auto bootstrap conditions

Previously we could double and have nodes join without data, now when
auto bootstrap is true we do not return the current node as a seed ever.

• Provide an overwrite method to force Priam to replace a particular ip

This allows us to work around the A->B->C replacement problem where
Priam get's confused about who to replace