Assess Versioning on the system

Every piece on the system ought to be versioned in some way.

- LO and all modules should be versioned
- Including the extension
- What about sub-modules within LO?
- Modules should say
- `Requires Learning-Observer==1.0` - We can use pip's version installation format
- `Requires [feature]`
- Modules should be able to define migrators between versions of incoming events
- Extension should send version of itself to LO
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The issue names no files, tests, or entry points; start by mapping Learning Observer, its modules, the extension, sub-modules, and incoming events. Turn the listed version, dependency, feature-requirement, migration, and extension-reporting questions into an agreed design, with clear compatibility and completion criteria.

Written by the indexing model from the issue text.