v1.17: rpc-sts: add config options for stake-weighted qos (backport of #197)

[mergify]

Problem

no simple way to configure an rpc node to send transactions to staked peer(s), as per stake-weighted qos

Summary of Changes

• adds --rpc-send-transaction-tpu-peer HOST:PORT to specify a specific tpu peer to send transctions to, instead of the current leader. this argument may be passed multiple times.
• adds --rpc-send-transaction-also-leader to continue sending to the current leader even though tpu peers have been specified with --rpc-send-transaction-tpu-peer HOST:PORT

---

This is an automatic backport of pull request #197 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of f41fb84 has failed:

On branch mergify/bp/v1.17/pr-197
Your branch is up to date with 'origin/v1.17'.

You are currently cherry-picking commit f41fb84e15.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   send-transaction-service/src/send_transaction_service.rs
	both modified:   validator/src/cli.rs
	both modified:   validator/src/main.rs

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[t-nelson]

cc/ @sakridge for stable bp approval

[CriesofCarrots]

Conflicts need fixing

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 62.50000% with 6 lines in your changes are missing coverage. Please review.

Project coverage is 81.6%. Comparing base (4d499a3) to head (7e63edd).
Report is 2 commits behind head on v1.17.

Additional details and impacted files

@@           Coverage Diff           @@
##            v1.17     #340   +/-   ##
=======================================
  Coverage    81.6%    81.6%           
=======================================
  Files         806      806           
  Lines      219237   219251   +14     
=======================================
+ Hits       178998   179025   +27     
+ Misses      40239    40226   -13