Add general protocol information to the exporter

[rickstaa]

Is your feature request related to a problem? Please describe.

It would be nice to show general LivePeer protocol information to the exporter, similar to the data displayed on the https://explorer.livepeer.org/ page.

TODOs

• Add daily fees paid (i.e. livepeer_exporter_protocol_fees_paid).
• Add daily participation rate (i.e. livepeer_exporter_protocol_participation_rate).
• Add daily inflation rate (i.e. livepeer_exporter_protocol_estimated usage).
• Add daily delegators count (i.e. livepeer_exporter_protocol_delegators).
• Add daily orchestrators count (i.e. livepeer_exporter_protocol_orchestrators).
• Current round progress (e.g. livepeer_exporter_protocol_current_round_blocks_remaining, livepeer_exporter_protocol_current_round_time_remaining, livepeer_exporter_protocol_current_round_progress).
• Current round fees (i.e. livepeer_exporter_protocol_current_round_fees).
• Current round rewards (i.e. livepeer_exporter_protocol_current_round_rewards).

Describe the solution you'd like

We can fetch this information from the following endpoints:

• https://explorer.livepeer.org/api/usage
• https://explorer.livepeer.org/_next/data/xe8lg6V7gubXcRErA1lxB/orchestrators.json
• https://explorer.livepeer.org/api/current-round

Describe alternatives you've considered

No response

Additional context

No response

[rickstaa]

While I may not personally utilize this at the moment, I'm open to incorporating it into the system if there's significant interest from the community 👍🏻. Additionally, I welcome pull requests from individuals keen on contributing this feature 🚀.

[rickstaa]

Some of these protocol metrics might also be directly added to the go-livepeer binary monitoring system since they are already retrieved there 🤔.