Multi-remote scenarios are not handled well

[rraval]

git nomad sync assumes a single coordination repository. Example:

flowchart BT
    node1 <-- syncs refs --> origin
    node2 <-- syncs refs --> origin
    node3 <-- syncs refs --> origin

There should be a decent workflow for multi-remote setups:

flowchart BT
    node1 <-- syncs refs --> node2
    node1 <-- syncs refs --> node3
    node2 <-- syncs refs --> node3