change(rpc): generate coinbase transactions in the getblocktemplate RPC

[teor2345]

Motivation

This PR generates coinbase transactions when the getblocktemplate RPC is called.

Solution

Generate the coinbase transaction in the getblocktemplate RPC:

• Add coinbase creation to zebra-chain
• Add coinbase creation and miner subsidy to zebra-consensus

Related changes:

• Add the miner config to the GetBlockTemplateRpcImpl
• Add a getblocktemplate-rpcs feature to zebra-chain

Related fixes:

• Fix missing feature dependencies in zebra-consensus
• Provide fake valid block heights to getblocktemplate RPC tests
• Rewrite check_script_form() so it is easier to read

Testing:

• Add a getblocktemplate.coinbase_tx deserialized transaction snapshot
• Update the getblocktemplate RPC snapshots

Closes #5453.

Review

This is a routine change, it might help getting two people to review it.

Reviewer Checklist

• Will the PR name make sense to users?
  • Does it need extra CHANGELOG info? (new features, breaking changes, large changes)
• Are the PR labels correct?
• Does the code do what the ticket and PR says?
• How do you know it works? Does it have tests?

Follow Up Work

I split #5579 out of #5453, because the state request wasn't ready yet.

[codecov]

Codecov Report

Merging #5580 (6cbc9f9) into main (8d9c3ec) will decrease coverage by 0.04%.
The diff coverage is 76.74%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5580      +/-   ##
==========================================
- Coverage   78.83%   78.78%   -0.05%     
==========================================
  Files         305      305              
  Lines       38127    38160      +33     
==========================================
+ Hits        30056    30064       +8     
- Misses       8071     8096      +25     

[oxarbitrage]

Looks really good.