add test marks to fernet so backends without cipher (or AES/CBC) will skip
add test marks to fernet so backends without cipher (or AES/CBC) will skip

Ayrx/cryptography,bwhmather/cryptography,sholsapp/cryptography,bwhmather/cryptography,Lukasa/cryptography,skeuomorf/cryptography,Hasimir/cryptography,dstufft/cryptography,dstufft/cryptography,dstufft/cryptography,Lukasa/cryptography,Ayrx/cryptography,kimvais/cryptography,dstufft/cryptography,sholsapp/cryptography,Ayrx/cryptography,Lukasa/cryptography,sholsapp/cryptography,Hasimir/cryptography,dstufft/cryptography,skeuomorf/cryptography,kimvais/cryptography,Hasimir/cryptography,Ayrx/cryptography,skeuomorf/cryptography,Hasimir/cryptography,bwhmather/cryptography,kimvais/cryptography,kimvais/cryptography,bwhmather/cryptography,skeuomorf/cryptography,sholsapp/cryptography