Add @include directive for Bicep templating

[flanakin]

⚠️ Problem

There are some common patterns that we'll use in multiple bicep files that could be error prone when repeated often or introduce maintenance burden when needing to update them.

🛠️ Solution

Add an option to include reusable files using our Bicep templating. Something like:

// @include ../../include/telemetry.bicep

Consider explicit directives for the most common scenarios, like telemetry.

// @telemetry 'unique-id'

🙋‍♀️ Ask for the community

We could use your help:

1. Please vote this issue up (👍) to prioritize it.
2. Leave comments to help us solidify the vision.