media-gfx/brother-scan4-bin: rewrite using ebuild functions

[EvaSDK]

Basically the same kind of modifications I did for MFC-9340CDW.

• Use regular ebuild fonctions to control file installation and permission. Install udev rules to handle scanner access for currently logged in user.
• Add quotes around variables that need them.
• Add missing dependency on libnsl.
• Drop older revisions with unreachable source files.

There is probably more to do but this got me a working scanner (over USB right now). Also please comment if you wish I try to find some time to apply this to other ebuilds in the overlay.

[stefan-langenmaier]

Thanks again.

Sure, if you can take some time to update some ebuilds. :+1: They are getting a little stale. :( I didn't know about the udev rule.