Issue #00005559

Added utility methods to encrypt and decrypt Strings

We added

WGA.encryptString(String text)
WGA.decryptString(String secret)

WGA.encryptString() returns the encryped String, WGA.decryptString() returns the descrypted String.

Encryption (currently AES, 128 bit) is done based on the key file "openwga.key" that is individually generated on each OpenWGA installation. This means that normally encrypted strings can only be decrypted on the same server.

If decryption is needed on a different server (f. e. if stored in an item and replicated to a foreign server) make sure both servers use the same key file openwga.key.