Take manufacturer from card info if available

Card:

• Parse MANUFACTURER card info value
• Add possibility to set manufacturer (e.g. for old versions of gpg)

OpenPGPCard, P15Card:

• Remove manufacturer
• Remove now obsolete overrides of operator==

ReaderStatus:

• Use fallback for guessing the OpenPGP card manufacturer from the serial number, if MANUFACTURER isn't included in card info
• For PKCS#15 cards this fallback isn't necessary

• GnuPG-bug-id: T4876