[BUGFIX] Render PDFs and MP3s in FSC.

Add rendering for PDFs by reusing the one for images. MP3s can be
rendered with the video section.

Resolves: #71502
Resolves: #71474
Releases: master
Change-Id: I90b80c2885457bd14de5edfea7a7379fe949e903
Reviewed-on: https://review.typo3.org/44688


Tested-by: Wolfgang Wagner <wolfgang.wagner.fn@gmail.com>
Reviewed-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Daniel Goerz <ervaude@gmail.com>
Reviewed-by: Frans Saris <franssaris@gmail.com>
Reviewed-by: Steffen Müller <typo3@t3node.com>
Tested-by: Steffen Müller <typo3@t3node.com>