Provide a way to specify list of codecs in order of priority

[farindk]

When there are several encoders / decoders for the same format, we might want to prefer hardware codecs over software, but they may have limitations on their maximum supported sizes, bpp, ... (see comment in: #1072).
We need to extend the plugin API to allow querying whether a format can be processed. Moreover the user must be enabled to specify a list of codecs to use, ordered by priority. Those will be queried after each other until a plugin is found that can process the data.