[WIP] Draft of v2.1 - Refactor SP Builder classes #595

Job	Run time
rubocop	18s
Unit test (ubuntu-20.04, 3)	1m 43s
Unit test (ubuntu-20.04, 3.1)	1m 50s
Unit test (ubuntu-20.04, 3.4)	1m 47s
Unit test (ubuntu-20.04, jruby-9.4)	2m 26s
Unit test (ubuntu-20.04, 3.2)	1m 45s
Unit test (ubuntu-20.04, 3.3)	1m 46s
Unit test (macos-latest, jruby-9.4)	2m 13s
Unit test (windows-latest, 3.4)	3m 47s
Unit test (macos-latest, 3.2)	1m 30s
Unit test (macos-latest, 3)	1m 32s
Unit test (macos-latest, truffleruby)	2m 31s
Unit test (windows-latest, 3)	3m 45s
Unit test (ubuntu-20.04, truffleruby)	3m 31s
Unit test (windows-latest, 3.1)	3m 22s
Unit test (macos-latest, 3.4)	1m 31s
Unit test (macos-latest, 3.3)	1m 31s
Unit test (windows-latest, 3.3)	3m 25s
Unit test (macos-latest, 3.1)	1m 30s
Unit test (windows-latest, 3.2)	3m 19s
finish	0s
	45m 2s

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