Mining Rule Engine: Blue Only Mergeset Rule

[coderofstuff]

Splitting off #634 into parts. This is Part 3/3. Depends on #655

Blue-Only Mergeset Rule

Goal:
Reduce the built_block_template time by excluding red blocks from the mergeset.

Rule:
Exclude any red blocks from the mergeset. All reds are treated as "bad reds".

Metric:

Field	Tracking
build_block_template_within_threshold	Increment if BBT from virtual completed within 100ms
build_block_template_above_threshold	Increment if BBT from virtual completion took longer than 100ms

Trigger:

• there were BBT calls that took longer than the threshold AND
• no BBT call completed within the threshold

Recovery:

• a BBT call completed within 100ms AND
• a merge bound amount of blocks has passed since the trigger