Add support for encrypted values in property files in branch 2 0 x

In order to support encrypted values in property files (e.g. jdbc password) I've implemented a small solution which is using Jasypt. One can now use encrypted values in liquibase property files (e.g. the param 'password' in defaultsFile). Such values are encrypted with Jasypt PBE (password based encryption) and are prefixed with 'ENC' [ e.g. password=ENC(hsaldeu35w30dnvldgw26749) ] The password needed for decrypt such values can stored in an environment variable. The name of this variable can given to Liquibase by the new command line parameter --pbePasswordVariable. At runtime, the value of this environment variable is read and given as Jasypt PBE configuration in order to decrypt the parameter and put it's value into the appropriate field (like all other liquibase parameter)