Contrib component metadata

As a user exploring the java ecosystem, I would like to know what types of extensions and tools are available to me, aside from the standard java agent instrumentations.

As part of the Ecosystem Explorer Project, we would like to inventory the extensions produced by this repo so that we can expose them as part of our registry. (https://github.com/open-telemetry/opentelemetry-ecosystem-explorer/issues/22)

In order to do that, we would like to introduce a metadata file for each component in this project that contains some basic information, similar to how components are documented in the collector (example), and in the java instrumentation project (example).

References:

• Collector metadata schema information
• Java instrumentation metadata schema information

Requirements:

• Review all contrib components and identify metadata fields to create a proposed schema
• Create and document schema definition
• Populate metadata files for all components

Start by reviewing the referenced Collector and Java instrumentation metadata schemas, then inspect all components in this repository to identify the fields they need. Document the proposed schema and populate a metadata file for every contrib component; completion means the schema is defined and all components are represented.