* Fixes#1985
- add migration AddMediaAttachmentMeta, which add meta field to media_attachments
- before saving attachment, set file meta if needed
- add meta in api
* add spec
* align the “size” format for image and video
* fix code climate
* fixes media_attachment_spec.rb
Create MediaAttachment but without actual file download when domain is blocked with reject_media set to true
Clean up old media files when creating a new domain block with reject_media set to true
Return remote_url in media attachments API if local file is not present
Undo domain block action in admin UI
Ability to enable reject_media from admin UI
for avatars/headers, resize avatars down to 120x120 instead of 300x300. Set cache headers on S3 stuff, also
make it private (aka only accessible via expiring links to prevent hotlinking)
Eugen Rochko
Francis Chong