feat: add separate flag for metrics

[AntiTyping]

Refactors debug and metrics servers into two separate servers

• adds --enable-metrics-server
• uses 127.0.0.1 as the default address for debug and metrics servers
• uses port 5184 as the default port for metrics server
• adds metrics-listen-addr setting to config.yaml
• rly config init will generate the following config
• renamed api-listen-addr to debug-listen-addr
• renames --debug-addr to --debug-listen-addr to be consistent with config

global:
    debug-listen-addr: 127.0.0.1:5183
    metrics-listen-addr: 127.0.0.1:5184
    ...

• [x] manually test the relayer to make sure it works today
• [x] add unit tests to make sure it works today and in the future

[freak12techno]

Just saying, 9100 is a default port for node_exporter, which is widely used everywhere for HW metrics collection, so it might clash.

[jtieri]

Did we still want to ensure backwards compatibility in this PR by adding back the old flags/old fields in the config, and then mark things deprecated for one release?

If not then i think this is mostly ready to merge and we can just cut a new major release

[AntiTyping]

@jtieri I restored the legacy flags and settings in this commit https://github.com/cosmos/relayer/pull/1504/commits/6cb53dcd407683e39d5fec051156fbaf2779b894