[FEATURE] minify task: Use workerpool for terser

[RandomByte]

Based on #700:

• Changed logging to verbose
• Added option 'useWorkers' to processor. Implicit activation through
  taskUtil parameter seemed a bit odd. Moved that to the minify task
• Added JSDoc

[coveralls]

Coverage: 94.623% (+0.01%) from 94.609% when pulling 28efc4c on minify-task-workerpool into 34b1e6f on main.

[RandomByte]

I did some benchmarks according to our documentation, comparing this PR to the current main branch:

openui5-sample-app

ui5-builder Ref	Command	Mean [ms]	Min [ms]	Max [ms]	Relative
main (9aa8b1c)	ui5 build	748.5 ± 20.9	725.2	803.0	Baseline
minify-task-workerpool (75463c3)	ui5 build	796.5 ± 33.7	739.3	870.6	+7%

sap.ui.core

ui5-builder Ref	Command	Mean [s]	Min [s]	Max [s]	Relative
main (9aa8b1c)	ui5 build	10.915 ± 0.219	10.718	11.451	Baseline
minify-task-workerpool (75463c3)	ui5 build	7.790 ± 0.061	7.659	7.856	-29%

OpenUI5 testsuite (including dependencies)

ui5-builder Ref	Command	Mean [s]	Min [s]	Max [s]	Relative
main (9aa8b1c)	ui5 build --all	86.258 ± 1.258	84.060	87.747	Baseline
minify-task-workerpool (75463c3)	ui5 build --all	73.263 ± 1.187	70.492	74.629	-15%

Specs: MacBook Pro M1 Max

[codeworrior]

LGTM.

If myFun() in the test fixtures was meant to be myFunc(), you might want to fix that. But the tests still make sense in their current state. A reader just may wonder about the name mismatch.

[codeworrior]

LGTM