Support minimal Djikstra era and Leios devnet

[kderme]

We want to support the Leios devnet respin. We need

• a minimal Djikstra integration
• a minimal Leios integration, supporting new block format
• optionally extending the schema with Leios specific data

Depends on input-output-hk/ouroboros-leios#898
and input-output-hk/ouroboros-leios#871