Convert @deephaven/utils package JS to TS

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There is a lot of existing JavaScript in the code. This task is to convert the @deephaven/utils package from JS to TS. Should be incremental (eg. file a PR when one file is done).

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@spasovski There's just a couple more test.js files that need to be converted to test.ts, then we can close out this ticket

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Fixed with #98