Improve the ESP8266 secure/nonsecure switch

The ability to switch between insecure and secure connection when using ESP8266 boards is a good change, but it would be more helpful if the change were controllable via code or pre-processor definition.

This would mean there is no need to change the distributed libraries

Ideally, we could have a simple preprocessor macro such as
#define AIO_ESP8266_SECURE 1

Alternatively, just create another class

Start by locating the existing ESP8266 secure/nonsecure connection switch in the library and reviewing how the distributed libraries currently select it. Done means callers can choose the connection mode through a preprocessor definition such as AIO_ESP8266_SECURE, or through a separate class, without editing distributed library files.

Written by the indexing model from the issue text.