Make rfbridge module generic RF<->MQTT

[mcspr]

Current RF_SUPPORT (rf.ino) does not provide MQTT API nor does allow sending data. And current ITEAD_SONOFF_RFBRIDGE (rfbridge.ino) allows to use rcswitch directly. They can be combined into one module.

Some things to change:

• decide at compile time what logic to use (rcswitch or efm)
• rename either RFB_DIRECT or RF_SUPPORT
• combine RF_PINs and RFB_TX_PINs definitions (pending gpio settings in config, namespace is the same)

[iprak]

I don't think there is any rf.ino module, right ? I too was quite confused about what RF_SUPPORT is meant for. I wanted to use basic 315Mhz Tx/Rx modules to control a switch so ended up faking it as ITEAD_SONOFF_RFBRIDGE with RFB_DIRECT and everything seems to be working even the MQTT part.

[mcspr]

It was combined with rfbridge: #1435
Although it is still kinda confusing. See #1693, some tests would be appreciated.