Use the OpenTelemetry Collector Builder

[puckpuck]

Feature Request

Inspired perhaps by this blog post from @codeboten, I wonder if we can move from specifying a collector image to using the collector builder instead with a definition file that vendors can easily modify/augment and deploy.

It follows best practices, where you should know precisely what your collector has. It can also mitigate future security vulnerabilities that may appear in plugins not used by the demo.