Add Apple media icons

[cdonnellytx]

Adding some additional file extensions to the config for file formats I have on my Apple devices.

They include:

• .3gp and .3g2, ~~used for video on the first couple of iPhones~~. Probably from a BlackBerry.
• .heic - the HEIF image format
• .m4v - Video format used by ~~iTunes~~ Apple TV app.

I did not add .hevc as it appears that HEVC files are just saved with the standard .mov extension.