feat: migration parser

[skl]

First attempt at a migration tool, see unit tests for usage.

• Uses the lezer PromQL parser with full access to the AST
• Uses the TypeScript Compiler API to generate TypeScript code
  • I did first create the source file using the full Compiler API but that added hundreds of lines of code. So I simplified and went with plain old template strings instead. However, to proceed further with the tool, may need to revert back to the full Compiler API. Ran out of time to take this further in the Hackathon though.

Example

Input PromQL string:

foo{bar="baz",qux!~"quux"}

Output TypeScript code:

const foo = (values: {
    bar?: string;
    qux?: string;
}) => new Expression({
    metric: "foo",
    values,
    defaultOperator: MatchingOperator.equal,
    defaultSelectors: [{ label: "bar", operator: MatchingOperator.equal, value: "" }, { label: "qux", operator: MatchingOperator.notRegexMatch, value: "" }],
}).toString();