Create knowledgebase_quickstart.js

[v-jaswel]

Purpose

This adds quickstart code for creating, downloading, updating, publishing, and deleting a knowledgebase.

Does this introduce a breaking change?

[ ] Yes
[x] No

Pull Request Type

What kind of change does this Pull Request introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[x] Documentation content changes
[ ] Other... Please describe:

How to Test

• Get the code.
• Install Node.js if you don't have it already.
• Set QNAMAKER_SUBSCRIPTION_KEY and QNAMAKER_REGION environment variables.
• Run the code.

What to Check

Verify that the following are valid

• Code should run and produce output without any errors.

Other Information