3. change(rpc): Add fee and sigops fields to getblocktemplate transactions

[teor2345]

Motivation

We need to add a mempool query to get the fee and sigops fields for the getblocktemplate RPC.

Closes #5454
Depends-On: #5496

Specifications

https://zcash.github.io/rpc/getblocktemplate.html

And whatever zcashd does.

Solution

• Add a new FullTransactions mempool request
• Return VerifiedUnminedTx with a new legacy_sigop_count field
• Add the fee and sigops fields to the transaction templates
• Add conversions from VerifiedUnminedTx to the block header roots
• Update tests for the new API

Review

I think @oxarbitrage is reviewing this PR series, but anyone else can review it as well.

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

The rest of the getblocktemplate RPC, probably the coinbase transaction or state request next

[codecov]

Codecov Report

Merging #5508 (985e2db) into main (1424115) will decrease coverage by 0.19%.
The diff coverage is 23.91%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5508      +/-   ##
==========================================
- Coverage   78.91%   78.72%   -0.20%     
==========================================
  Files         305      305              
  Lines       38061    38099      +38     
==========================================
- Hits        30037    29993      -44     
- Misses       8024     8106      +82     

[arya2]

Looks good

[oxarbitrage]

Looks good, lets try Arya suggestion at least for the one marked as allow(dead_code) before merging.

[teor2345]

Job failure but not a PR failure, see #5494 (comment)