[feature request] Support accounts in the Blockrelay config section

[SpontaneousOverthrow]

Rewriting proposerconfig in the blockrelay section based on accounts from the accountmanager section, not based on a single validator. In my case, I have different accounts with multi keys(about 200 for each). For each account I need to specify a different `fee recipient`. And current config is a bit messy now with a lot of copypaste.

[mcdee]

This feature should now be available in the https://github.com/attestantio/vouch/tree/execution-config-v2 branch. If possible, please compile this branch and run it in your test environment to confirm that it meets your requirement. If not, please read https://github.com/attestantio/vouch/blob/execution-config-v2/docs/executionconfig.md for the same.

[SpontaneousOverthrow]

ty, gonna test next week or so

[mcdee]

Any feedback on this PR? I'm looking to merge it in the coming week so any information you may have on it would be appreciated.