Step 1.1 - Create graphql_known_operations from webpack plugin

• DRAFT: Full Context MR
• Step 1.1 - Create graphql_known_operations from webpack plugin
• Step 1.2 - Add ApplicationContextTracer to Graphql Schema
• Step 2 - Add LoggerTracer to Graphql Schema
• Step 3 - Add MetricsTracer to Graphql Schema

What does this MR do and why?

In upcoming MR's, we need the ability to distinguish between operation names we know about (and want to record), and operation names we don't care about (see relevant comment). This MR introduces a webpack plugin to output a graphql_known_operations.yml file which can be read from the BE. This MR also abstracts a bit of BE code used to read the Webpack manifest.json, so it can be reused to read the graphql_known_operations.yml.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #331697 (closed)