Added initial support for Oukitel Smart Switch. This is a 2 outlet plug
that has the same pinout as the YiDian XS-SSA05.

* send all ws config at once on start
* reduce ws json overhead by creating message buffer manually
* use k:[values] instead of k1:value1, k2:value2 etc. for lists

This reverts commit 7ad0e3a02b.

- Heartbeat mode and interval configuration added to WebUI ADMIN page
- New option HEARTBEAT_REPEAT_STATUS: on device startup full heartbeat information and after HEARTBEAT_INTERVAL only STATUS report.
- Enhanced first heartbeat message - on device startup it will send heartbeat after ntpSynced will be true to get device time.

P.S. Code is tested. Web part is not compiled, and not tested. I hope it will work :)

* Merge RF and RFBridge code

* Keep rfbridge.ino filename

* Corrected #if checks

* Make RF_DEBOUNCE and RF_LEARN_TIMEOUT configurable

* Fix compile warnings with platform_latest

* Added the configuration for the second generation OBI devices.

* Added link to the OBI Wifi Schuko Plug V2 as well as included the device in the readme.

* Restored the default configuration accidentially changed by a previous commit.

* Renamed the OBI-V2 device to EUROMATE_WIFI_STECKER_SCHUKO_V2 as suggested by mcspr.

* Fixed spelling of comment to the proper wording Schuko.