Details:
	Added a new global bool system variable 'innodb_dedicated_server'
	with default value ON.
	When this variable is set to ON, then innodb_buffer_pool_size and
	innodb_log_file_size are autoscaled based on system memory.
	Also innodb_flush_method is set to O_DIRECT_NO_FSYNC if supported.

	A new component service 'system_variable_source' is also added which
	exposes a method named 'get' which could be used to get the SOURCE of
	a given system variable name.

	Reviewed by : thirunarayanan.balathandayuth@oracle.com
	              darshan.m.n@oracle.com
	              venkata.sidagam@oracle.com
	RB : 16832