Add protocol version information to fields on `NetworkParameters`

[arya2]

Motivation

We want to make these values configurable on Testnets:

• INITIAL_MIN_NETWORK_PROTOCOL_VERSION
• CURRENT_NETWORK_PROTOCOL_VERSION
• min_specified_for_upgrade

See https://github.com/ZcashFoundation/zebra/pull/7924#discussion_r1385877140.

Outdated:

These have already been added. - [FUNDING_STREAM_HEIGHT_RANGES](https://github.com/ZcashFoundation/zebra/blob/main/zebra-consensus/src/parameters/subsidy.rs#L107) - [FUNDING_STREAM_ADDRESSES](https://github.com/ZcashFoundation/zebra/blob/main/zebra-consensus/src/parameters/subsidy.rs#L116)

Possible Design

Check what values zcashd uses for Regtest and either:

• Add them to these HashMaps for Testnet with Regtest parameters (this support custom testnets, only Regtest), or
• Add them as fields in NetworkParameters and set the Regtest values in Network::new_regtest (#7839):

[arya2]

This isn't a priority right now

[arya2]

We still want to move INITIAL_MIN_NETWORK_PROTOCOL_VERSION to a field on testnet::Parameters.