Create pre-release pipeline

[hallvictoria]

This PR aims to streamline the process for releasing alpha / beta / experimental versions of the NodeJS library from GitHub branches.

It introduces a new pipeline that:

1. Performs a build of the NodeJS npm package
2. Publishes a new version using the built artifact
3. Creates a GitHub tag and Release Note for the specified version

Steps for running:

1. Run pipeline: Pipelines - Runs for nodejs-library.prerelease
2. Select appropriate branch
3. Uncheck dry-run
4. Provide GitHub PAT (used for creating tag & release note) (optional)

Notes:

• ADO pipelines can either be pulled from an ADO repo or a GitHub repo -- not both. Creating a separate pipeline allows for the main release branch to only run for safe, ADO branches.
• The artifact published is not an official build. This is okay for pre-releases

Sample run (on this branch): https://dev.azure.com/azfunc/internal/_build/results?buildId=224393&view=results