Caching of media files

Adds a variety of caching methods for media files for media playback. Files originating from the file system can be cached in memory, and files originating from a database can be cached in memory or on the file system. Media not present in the cache will be loaded as before.

Media cache provisioning

The media cache can be populated on startup or automatically on demand. Manual loading of media into the cache via a CLI command is also available. The contents of the cache can be inspected via CLI command as well, and the sizes of the caches are exported via the usual statistics outputs.

Media cache cleanup

Cache entries can be automatically removed after going unused for a certain amount of time. A CLI command to manually remove cache entries, or clear out the entire cache, is also available. Alternatively, entries in the media cache can be automatically refreshed and reloaded in regular intervals.

Music on hold functionality introduced.

Music on hold functionality provides a streaming of media towards opposite call party when being held, based on a given media source (blob, file on the system or DB stored data).

It is only available if compiled with transcoding support. This functionality is available only for the offer/answer model, hence no other scenarios like publish or subscription related are supported with it.