Node: Reobserve with custom endpoint

[bruce-riley]

This PR adds support for the reobserve-with-endpoint admin command.

Don't be alarmed by the size of this PR. 900+ lines are generated protobuf code. Also the code in handleReobservationRequest in Solana and EVM is mostly just code moved into a function so it can be reused.

Tests performed:

• Sepolia new observations still works
• Sepolia standard reobservation still works
• Sepolia with custom endpoint works
• Solana new observations still works
• Solana standard reobservation by account still works
• Solana standard reobservation by transaction ID still works
• Solana by account ID with custom endpoint works
• Solana by transaction ID with custom endpoint works
• Chain that is not enabled returns "chain X does not support reobservation by endpoint"
• Chain other than Solana or EVM that is enabled returns "chain X does not support reobservation by endpoint"
• Pointing at the wrong EVM chain returns "evm chain ID miss match".

[johnsaigle]

Looks good, made some suggestions to simplify the code.

[bruce-riley]

Note: Once #4116 is merged, the EVM version of Reobserve should be updated to call verifyEvmChainID before performing the reobservation.

[bruce-riley]

Now that #4116 is merged, I added a check to make sure the custom endpoint URL points at the correct EVM chain.