Add Geo limitation: secondary sites must use the same port for SSH as the primary

Problem to solve

Clone URLs for repositories on the Geo secondary sites have a bug of exposing primary node "external_url"

Short term fix for this bug implies that SSH ports for both primary and secondary sites are the same.

Despite this is true for 95+% of the time by coincidence, to ensure that this could be used as a rule, add it to the Geo limitations