Follow-up commit after merging support for XEP-0446: File Metadata Element
This is a follow-up commit after 441d6776447f ("Initial support for XEP-0446: File Metadata Element"). It includes the following changes
1. Use idiomatic provider design for FileMetadataElementProvider
2. Add XEP-0264 and XEP-0446 to the list of supported XEPs (both where
added with441d6776447f)
[urldata] Follow-up on initial merge of XEP-0103/0104 support
This is a follow-up on 198c51356dd8 ("Add initial support for XEP-0103
and XEP-0104: URL Address Information"), which
1. adds the entries to the support XEPs table
2. registers the provider
3. renames the package from url_address_information to urldata (aka.
the shortname of XEP-0130).
