Pluggable Balancers

[errfrom]

Closes Move balancer to a separate package with public API #1621

Extracted the default CTL transaction balancer into its own package: CTL Tx Balancing & Coin Selection #2

Pre-review checklist

• All code has been formatted using our config (make format)
• Any new API features or modification of existing behavior are covered with tests
• The template (templates/ctl-scaffold) has been updated
• The changelog has been updated under the ## Unreleased header, using the appropriate sub-headings (### Added, ### Changed, ### Removed, ### Fixed), and the links to the appropriate issues/PRs have been included

[marcusbfs]

Looking great. Two things:

• the test Evaluation with additional UTxOs with native scripts is failing
• A new version of the packaget-set containing the balancer package must be released. Then, update CTL (and the scaffold template) to use it

[marcusbfs]

LGTM

[KristianBalaj]

The default balancer is in the Cardano.Transaction.Balancer AFAIU. But, it sounds too general namespace for me. Instead, it should be something more specific IMO, that describes it better.