mod_http_file_share: Add file size limit (default 10M)

mod_http_file_share: Validate that filename does not contain '/'

mod_http_file_share: Return proper error if unauthorized

mod_http_file_share: Add basic access control Partly lifted from mod_external_services

mod_http_file_share: Add support for external file upload service PUT /upload/:slot/:filename Authorization: Bearer JWT{ uploader, filename, filesize, filetype, exp }

mod_http_file_share: Let's write another XEP-0363 implementation This variant is meant to improve upon mod_http_upload in some ways: * Handle files much of arbitrary size efficiently * Allow GET and PUT URLs to be different * Remember Content-Type sent by client * Avoid dependency on mod_http_files * Built-in way to delegate storage to another httpd

util.interpolation: Add test for #1623

Merge 0.11->trunk

util.interpolation: Fix combination of filters and fallback values #1623

util.startup: Make installer_plugin_path relative to data directory Having it relative to current working directory is problematic since this depends on how Prosody was started and changes to the data directory during startup (but after this point).