Split `mithril-common` crate - Phase 1

[jpraynaud]

Why

We have worked on a split of the mithril-common crate in the issue #2175. We want to implement the second round of modifications that are mandatory to the rest of the split.

What

Implement the extraction of resource_pool, signed_entity_lock and transaction_preloader modules from the mithril-common crate.

How

• Extract the resource_pool module in a internal/mithril-resource-pool crate
• Extract the signed_entity_lock modules in a internal/signed-entity/mithril-signed-entity-lock crate
• Extract the transaction_preloader modules in a internal/signed-entity/mithril-signed-entity-preloader crate
• Cleanup unneeded dependencies in the mithril-common crate (with cargo-machete)