Feature: Allow replication startup with any arbitrary point in time (given SCN)

[bersler]

Is your feature request related to a problem? Please describe.
To initiate replication the database must be available (either primary or standby) to extract a consistent copy of system tables containing copy of the schema at a certain starting time. This is very problematic.

Describe the solution you'd like
Add possibility to start replication with any given SCN (or point in time).

Describe alternatives you've considered
To do that one would need to restore a copy of the database at certain time (up to the minute database restore), copy the schema and use it as an initial schema for replication.

Additional context
This feature is not a must have to use replication but would certainly make replication configuration easier.

[bersler]

This feature is complicated to implement.. If there is a demand from users more focus could be given here.