Add option to allow modules to start even with error.

[becega]

For example using the Modbus master module. The slave might not be ready when the module init. If there is no slave the module will error and the rest of the system will not start.
This is intended behavior and was designed on the assumption that the system should not start on error.
We need to allow a Opt in option for allowing modules to start on error.
This options require 2 modification a configuration to select if a module can start on error.
Change in the init to change errors in init to warning.