New Keyring plugin called keyring_encrypted_file plugin is introduced which will
store keyring data in file local to server host which is encrypted using a password.
This plugin when installed must be provided with a password which will be used to
decrypt the file to read the contents of file. Similarly this password will be used
to encrypt the data which needs to be stored in the data file.

This WL also introduces keyring migration tool which is used to migrate keys from
one keyring plugin to another. This tool is embedded in mysql server, this when
mysqld is invoked with migration specific options, mysql server will ast like a
migration tool.