feat: Implement suport for several off-chain data sources

[mark-stopka]

Blockfrost support is already in the roadmap, but there are several alternatives to Blockfrost, additional ones should be added...

• [ ] Implement required abstraction level to enable multiple data providers
• [ ] Implement support for Blockfrost https://github.com/txpipe/oura/issues/92
• [ ] Implement support for Koios