Merge monitor endpoint flags

[corverroos]

Problem to Solve

Monitor has two flags which serve the same purpose --xfeemngr-rpc-endpoints and the standard --xchain-evm-rpc-endpoints. There should be no need to duplicate these flags, even if feemngr requires non-xchain-specific endpoints. Adding additional endpoints to --xchain-evm-rpc-endpoints doesn't and shouldn't break anything.

Proposed Solution

• Remove --xfeemngr-rpc-endpoints
• Add additional endpoints required by xfeemngr to --xchain-evm-rpc-endpoints in monitor

[corverroos]

Note the root cause is that netconf.AwaitOnChain iterates over the --xchain-evm-rpc-endpoints flags and waits for those chains to be registered. This is why the second --xfeemngr-rpc-endpoints was added. So we'll need a different workaround for new chains (height<1000) to ensure that we wait for all expected chains.