implements:
https://github.com/meilisearch/specifications/blob/develop/text/0085-api-keys.md
- Add tests on API keys management route (meilisearch-http/tests/auth/api_keys.rs)
- Add tests checking authorizations on each meilisearch routes (meilisearch-http/tests/auth/authorization.rs)
- Implement API keys management routes (meilisearch-http/src/routes/api_key.rs)
- Create module to manage API keys and authorizations (meilisearch-auth)
- Reimplement GuardedData to extend authorizations (meilisearch-http/src/extractors/authentication/mod.rs)
- Change X-MEILI-API-KEY by Authorization Bearer (meilisearch-http/src/extractors/authentication/mod.rs)
- Change meilisearch routes to fit to the new authorization feature (meilisearch-http/src/routes/)
- close#1867
