feat: builder for unsigned contract call

[yknl]

Migrated stacks-transaction-js PR from @hstove: stacks-archive/stacks-transactions-js#131

Description

Adds makeUnsignedContractCall function. This is built to be almost identical to the makeUnsignedStacksTokenTransfer function, which can accept one or more public keys. The actual makeContractCall, similarly, uses the unsigned variant to build the transaction, and then it simply signs the TX.

Type of Change

• New feature
• Bug fix
• API reference/documentation update
• Other

Checklist

• Code is commented where needed
• Unit test coverage for new or modified code paths
• npm run test passes
• Changelog is updated
• Tag 1 of @yknl, @zone117x, @reedrosenbluth for review

[codecov]

Codecov Report

Merging #841 into feature/monorepo-refactor will increase coverage by 0.06%.
The diff coverage is n/a.

@@                      Coverage Diff                      @@
##           feature/monorepo-refactor     #841      +/-   ##
=============================================================
+ Coverage                      77.04%   77.10%   +0.06%     
=============================================================
  Files                             72       72              
  Lines                           4321     4338      +17     
  Branches                         737      738       +1     
=============================================================
+ Hits                            3329     3345      +16     
- Misses                           957      958       +1     
  Partials                          35       35              

Impacted Files	Coverage Δ
src/builders.ts	71.38% <0.00%> (+1.38%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 124b5ca...ba2243e. Read the comment docs.

[hstove]

Thanks Ken!