5. change(rpc): Implement coinbase conversion to RPC TransactionTemplate type

[teor2345]

Motivation

We want to calculate miner fees and transaction roots, then generate transaction templates.

This does everything except actually generating a coinbase transaction.

Part of #5453.

Specifications

coinbase_txn, transactions, and some root fields in:
https://zcash.github.io/rpc/getblocktemplate.html

Solution

• Add conversion from coinbase Transactions into TransactionTemplates
  • Calculate the sigops using zebra-script, because we don't want to call the transaction verifier
• Add a Network field to the getblocktemplate RPC handler
  • The network and block height are needed to generate the coinbase transaction

Refactors:

• Split out a select_mempool_transactions() function
• Cleanup redundant dependencies

Review

Anyone can review this PR.

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

Actually generate the coinbase transaction

[codecov]

Codecov Report

Merging #5554 (9e899d9) into main (75f83fc) will decrease coverage by 0.05%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5554      +/-   ##
==========================================
- Coverage   78.84%   78.78%   -0.06%     
==========================================
  Files         305      305              
  Lines       38126    38127       +1     
==========================================
- Hits        30061    30039      -22     
- Misses       8065     8088      +23     

[arya2]

This looks good! There's a small merge conflict with the select_mempool_transactions refactor.

[teor2345]

@Mergifyio update

[mergify]

update

☑️ Nothing to do

• #commits-behind>0 [:pushpin: update requirement]
• -closed [:pushpin: update requirement]

[teor2345]

@Mergifyio update

[mergify]

update

✅ Branch has been successfully updated

[teor2345]

@Mergifyio update

[mergify]

update

✅ Branch has been successfully updated