Onramp upgrade & rollback flows [NONEVM-1297]

[toblich]

This PR supports emulating a CCIP minor version bump on the onramp. The bump is done per-lane (so, per dest-chain for the onramp). To do the bump, the owner should:

• Update the dest-chain configuration as needed (mostly in fee quoter)
• Invoke the new bump method in the router/onramp, which mostly just resets the sequence number for that lane

Then, to rollback, the owner should:

• Update the dest-chain configuration as needed (mostly in fee quoter)
• Invoke the new rollback method in the router/onramp, which mostly just restores the sequence number for that lane that was there before the last upgrade.

Caveats:

• As upgrades of CCIP minor version are not too often, we only support one consecutive rollback. We don't expect nor support rolling-back twice in a row, without having bumped again at least once in between
• It is up to the admin to update the fee quoter config accordingly with each operation, and bundling all changes in a single tx

[toblich]

@RensR if you want to review, this is the implementation of the onramp upgrade/rollback which we talked about and how to handle the sequence number accordingly. Just looking at this file is enough I think, no need to worry about the rest.

[PabloMansanet]

LGTM! Just two minor points on comments/clarity.

[github-actions]

Metric	tobi/onramp-upgrade-rollback	main
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