* Add image descriptions to searchable post content.

* Allow multi-line image descriptions.

* Request image descriptions in the same query as posts when creating the search index.

(see https://github.com/tootsuite/mastodon/pull/10036#discussion_r256551624)

* Add full-text search for authorized statuses

- Search API will return statuses that match the query
- Only for logged in users
- Only if you are author of the status,
- Or you were mentioned in it
- Or you favourited or reblogged it
- Configuration over `ES_ENABLED`, `ES_HOST`, `ES_PORT`, `ES_PREFIX`
- Run `rails chewy:deploy` to create & populate index

Fix #5880
Fix #4293
Fix #1152

* Add commented out docker-compose configuration for ES container

* Optimize index import, filter search results

* Add basic normalization to the index

* Add better stemming and normalization to the index

* Skip webfinger request if search query includes both @ and a space

* Fix code style

* Visually separate search result sections

* Fix code style issues