Register contexts at construct time

[kevinkucharczyk]

This PR makes the addon register context when components get instantiated, rather than on first render.

This has two benefits:

• components can initialize state that depends on parent contexts without having to wait for the first render
• a component can consume and provide the same context key without infinite reference errors: consume would read the existing context "above" the component, while provide would provide a new context to any nested children

[changeset-bot]

🦋 Changeset detected

Latest commit: 136df37

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
ember-provide-consume-context	Minor

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