Implement round robin for selecting transaction queue

[Mihajlo-Pavlovic]

Description

Implemented round robin as a tiebreaker when there are multiple queues with same minimal length

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Tested locally on nodes with 2 and 1 wallet, by doing multiple publishes.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[zeroxbt]

Isn't the current implementation more efficient ? If one of the tx queues is slower or stuck, why shouldn't we just add new txs to the queues with lower number of txs ?

[Mihajlo-Pavlovic]

@zeroxbt I added additional changes, now round robin is only used as tiebreaker