Further improvements to environment visualizer

[vansh284]

This pull request goes hand in hand with source-academy/frontend#2579. It also further simplifies the agenda to help with teaching.
Changes:

• Simplification of the model by resolving Env Viz: Avoid unnecessary block statements #1439, Env Viz: Avoid unnecessary markers #1441 and Env Viz: Avoid unnecessary break markers #1442.
• Support rest syntax Env Viz: cannot handle rest syntax #1445
• Refactoring of the envsteps from context to be an option parameter.
• Use the step limit in the ec-evaluator
• Environment instruction not pushed if it is the last item on the agenda.

[coveralls]

Pull Request Test Coverage Report for Build 5704033283

• 65 of 74 (87.84%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.02%) to 83.584%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/ec-evaluator/utils.ts	26	30	86.67%
src/ec-evaluator/interpreter.ts	39	44	88.64%

Totals
Change from base Build 5678796910:	-0.02%
Covered Lines:	10699
Relevant Lines:	12388

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💛 - Coveralls

[martin-henz]

Looks good!