[Add] Block Builder

[cschuchardt88]

Description

This adds BlockBuilder class for easy building of blocks.

Type of change

• Optimization (the change is only an optimization)
• Style (the change is only a code style for better maintenance or standard purpose)
• 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?

• Unit Tests

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my 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

[erikzhang]

Where will it be used?

[cschuchardt88]

Where will it be used?

No where at the moment. Ill be changing code to use this method, after PR is merged. Also its for SDK users. Note: no core developer will review unless I do it in stages or else it will sit for months or years. No one but me will review big PRs with too many changes. So I try to do one thing at a time.

[erikzhang]

I think the only place that can construct blocks is the consensus plugin? So should it be put into the consensus plugin?

[shargon]

Not needed now

[cschuchardt88]

@shargon what makes it not needed?