PQC updates and more

[drwetter]

• emphasize PQC is important to tackle NOW
• modernize protocol section (TLS =<1.1 is obsolete now)
• SMTP needed to be rephrased as realistically it cannot be avoided other than throwing the old far^W dinosaur protocol away
• yescrypt is often used under Linux at least these days.
• PBKDF2-HMAC-SHA-256 --> PBKDF2-HMAC-SHA-512 (sha2 is not state of the art anymore but may suffice the next couple of year for this type of PW encryption if there are enough rounds an have salts. But we should recommend the best as reencryption often won't be done)
• remove 1st bcrypt instance so that it appears as legacy only