* begin refactor suggested as "step 2": https://github.com/ZcashFoundation/zebra/issues/7968#issue-2003245309
Squashed from multiple commits to enable partial rebase
* break out more little traits
* add activation implementation leveraging From<Network> for lrz::cons::
* for transfer of ownership I cannot return a type that's owned by the method
* hrp_sapling_extended_full_viewing_key
* complete implementation of interface of Parameters on Network reuse Parameters on zcash Network where possible
* move doc-comments to trait declarations (from impls)
* Simplify/complete Parameters impl for Network
* Add checkpoint_list method, move documentation, etc
* move last match network to inside network method
* add back comment
* use zcash_address for parameter types in zebra-chain
* use inherent methods instead of big parameters passthrough
* revert to implementation of From on zcash_primitives::..::Network vs &zcash_prim...
* move match
* add test to block maximum time rule
* update changelog
* finish porting target_difficutly_limit
* remove obscelete code comment
* revert non-functional change
* finish migrating target_difficulty_limit, checkpoint_list
* update changelog
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Co-authored-by: Hazel OHearn <gygaxis@zingolabs.org>
3bef54b764