Implement the CSEP machine, along with macros

[s-kybound]

Description

This PR introduces the P component to the CSE machine, which tracks a set of transformers with which we can use to expand macros into simpler forms. This enables the Scheme language to use macros in Source Academy

Type of change

• 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)
• Documentation update
• Code quality improvements

Checklist

• I have tested this code
• I have updated the documentation

[coveralls]

Pull Request Test Coverage Report for Build 11678254034

Details

• 438 of 557 (78.64%) changed or added relevant lines in 10 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 81.435%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/cse-machine/utils.ts	27	28	96.43%
src/cse-machine/continuations.ts	8	10	80.0%
src/cse-machine/interpreter.ts	33	36	91.67%
src/cse-machine/scheme-macros.ts	164	190	86.32%
src/cse-machine/patterns.ts	189	276	68.48%

Files with Coverage Reduction	New Missed Lines	%
src/cse-machine/utils.ts	1	91.55%

Totals
Change from base Build 11140006313:	-0.2%
Covered Lines:	11423
Relevant Lines:	13626

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💛 - Coveralls