This WL introduces an option to persist global dynamic configuration variables,
for example like SET PERSIST innodb_flush_log_at_timeout= 14;. Configuration
variables over a connection are lost after server restart. This WL provides
DBAs a way to store configuration variables in a persistent way and allow
server to read and apply all those variables which are persisted during a
restart. A new config file name mysqld-auto.cnf will be created in datadir
when a variable is persisted. This new config file is in JSON format.

In addition to the persistence we add a performance schema table called
"variables_info" which will have an entry for all configuration variables.
This table will also have information about where the current value came
from and some additional information about the variable. The historical
configuration files can be used as before.

This WL provides a read only system variable named persisted-globals-load
which provides an option to enable/disable reading of persistent config file.