package/macosx: enhanced the codesign script to add a designated signature to enhance its compatibility

Note 3 things

 - the included hashes are common knowledge, non-exploitable and hence don't constitute a security issue

 - you need a valid Developer ID private key to create GateKeeper compatible signatures

 - If you don't use VideoLAN's Dev ID, that's noticable but doesn't limit the app's behavior in any detail.

This commit also limits the signing process to the compiled lua scripts and no longer signs the entire lua folder since this would limit the usage experience and it isn't reasonable either.
(cherry picked from commit 41e20140b3bd4482cb02fe6eede5da471e57859d)