ast_stream_topology_create_from_format_cap() was setting the
stream->formats directly but not freeing the default formats.  This
causes a memory leak.

* ast_stream_topology_create_from_format_cap() now calls
  ast_stream_set_formats() which properly cleans up the existing
  stream formats.

When cloning a stream, the source stream's format caps _pointer_ is
copied to the new stream and it's reference count bumped.  If
either stream is set to "removed", this will cause _both_ streams
to have their format caps cleared.

* ast_stream_clone() now creates a new format caps object and copies
  the formats from the source stream instead of just copying the
  pointer.

ASTERISK-28870

Change-Id: If697d81c3658eb7baeea6dab413b13423938fb53