Add support for .RMI files in "Import MIDI"

[SubtotalAnt8185]

RMI files are basically midi files wrapped in a container. This container contains a header that is not recognized by Online Sequencer. In addition, it adds more data to the end of the file, invalidating the EOF check.
Usually, you can just grant the RMI file the ".mid" file extension. This works with all programs I've currently tried, but online sequencer still looks for the MIDI header bytes (which are just offset by the extra header).
Adding support for this would improve user experience when importing files with the RMI file extension without having to open up a hex editor and manually make changes to the header bytes, track headers, and the end of file.

Can we expect support for this somewhere in the future, or is it a lost cause?

Edit: If a tool that could already do this exists, then I don't believe support is needed for this entirely. However, Online Sequencer should notify you of the availability of the tool (if it exists) and ask you to use said tool to convert the file.

[Lopyt]

I dont think many people use that filetype, might not be worth it. If there is a significant amount of users though that may be a good idea