Move media related classes and interfaces from AttachmentModule into dedicated MediaModule
I have done some refactoring:
- briar-api
- Rename package org/briarproject/briar/api/media to org/briarproject/briar/api/attachment
- briar-core
- Rename package org/briarproject/briar/media to org/briarproject/briar/attachment
- Rename MediaModule to AttachmentModule
- briar-android
- Move Image* and Size from package attachment to attachment.media
- Create MediaModule (derive from AttachmentModule) and add to components that need it
- Increase visibility of some of the moved classes and create getters for fields that were previously accessed directly