CfgManager.Text skeleton

[francois-normandin]

Create the skeleton for the text-based support files such as INI, JSON, XML, CSV, etc.

[francois-normandin]

This base class will feature a process that manages saving to file when appropriate.
Saving to file will be immediate if "write delay" = 0.
Saving to file will be delayed indefinitely if "write delay" = -1.
Saving to file will be delayed by "write delay" to allow multiple changes to be concatenated into a single write-to-disk operation.