Auto-Config prepend_seq pattern match

[sward1557]

Is your feature request related to a problem? Please describe.
This feature is an addition to feature request #459 . This request is to have the autoconfiguration pattern match (beyond the origin) as in the prepend_seq.

Describe the solution you'd like
The goal here would be for the auto-config auto populates prepend_seq when generating from the exabgp session.

Describe alternatives you've considered
Since this is a requirement in our config there isn't an alternative.

Additional context
See issues #443 and #459