Array js functions

[pelikhan]

Finish Array object implementation.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array

Guide: https://microsoft.github.io/devicescript/contributing#add-core-javascript-apis

[sh33dafi]

Hi @pelikhan I'm interested in adding the missing implementations

[pelikhan]

Great!

• impl location: https://github.com/microsoft/devicescript/blob/main/packages/core/src/array.ts
• declarations: https://github.com/microsoft/devicescript/blob/main/packages/core/src/corelib.d.ts#L210
• tests: https://github.com/microsoft/devicescript/blob/main/devs/run-tests/24arraymap.ts

Feel free to break down implemetation in several PRs so that it helps the review.

[sh33dafi]

Created a first PR https://github.com/microsoft/devicescript/pull/520