Investigate the unification of Leios and block header specs

Currently, there is the [block header specification](https://github.com/IntersectMBO/ouroboros-consensus/blob/main/docs/agda-spec) which only deals with the sequential validation of block headers in Ouroboros Praos. On the other hand, there is a [specification of Linear Leios](https://github.com/input-output-hk/ouroboros-leios-formal-spec/blob/V1.0/formal-spec/Leios/Linear.lagda.md), that is, the specification of the Ouroboros Leios variant which is described in [CIP-0164](https://github.com/cardano-scaling/CIPs/blob/leios/CIP-0164). We need to investigate whether both specifications can be unified into one specification covering both topics.