Orchestrator operations: register, cuts, service URI, reward caller

[rickstaa]

Is your feature request related to a problem?

The Explorer has no orchestrator operations. Registering (transcoder), updating the service URI, changing reward and fee cuts, and setting a LIP-118 reward caller.

Describe the solution you'd like

An "Orchestrator" panel on the connected account's page, shown when the address is a registered orchestrator (or offers to register it), with:

• Register / update reward cut, fee cut, and service URI (BondingManager.transcoder, ServiceRegistry.setServiceURI)
• Set, view, and revoke the reward caller (BondingManager.setRewardCaller, transcoderToRewardCaller)

Describe alternatives you've considered

• livepeer_cli on a node holding the keystore (defeats cold storage)
• cast against the contracts (works, but not a UI, and Arbiscan does not show the new BondingManager methods on the proxy page yet)
• Housing this in livepeer/console instead. The Explorer seems the better fit since wallet connection and the protocol contracts are already wired up there, but either is fine; cross-reference if the console team wants it.

Additional context

• LIP-118: https://github.com/livepeer/LIPs/blob/master/LIPs/LIP-118.md
• go-livepeer client support (in review): feat: add LIP-118 reward caller support go-livepeer#4011