feat: Describe schemas in the DSL (#13) and Tool to infer initial schema (#12)

[MShahzaib]

feat: Describe schemas in the DSL (#13) and Tool to infer the initial dataset schema (#12)

Closes #[13], #[12].

Summary of Changes

• added "schema" declaration to grammar for describing a dataset's initial schema
• added ".sdsschema" extension for schemas
• added Tablesaw for inferring the initial dataset schema
• implemented schema inference for the initial dataset schema with a Unit test

[github-actions]

MegaLinter status: ✅ SUCCESS

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ CREDENTIALS	secretlint	yes		no	2.05s
✅ GIT	git_diff	yes		no	0.01s
✅ JSON	eslint-plugin-jsonc	1	0	0	1.01s
✅ JSON	jsonlint	1		0	0.23s
✅ JSON	prettier	1	0	0	0.48s
✅ JSON	v8r	1		0	4.15s
✅ KOTLIN	ktlint	14	0	0	27.22s
✅ MARKDOWN	markdownlint	1	0	0	0.38s
✅ MARKDOWN	markdown-link-check	1		0	0.45s
✅ MARKDOWN	markdown-table-formatter	1	0	0	0.32s

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[lars-reimann]

@MShahzaib For the sake of easier review, please split this into two PRs. The first one should only add the syntax for schemas (#13), and the second should only introduce the schema inference (#12).

[MShahzaib]

@lars-reimann okay i will do that !