OTA Upload Feature (#162)

* Improve restart behaviour under esp8266
* Backend to support firmware update over HTTP
* UI for uploading new firmware
* Documentation changes

interface/src/features/types.ts

@@ -4,4 +4,5 @@ export interface Features {
   mqtt: boolean;
   ntp: boolean;
   ota: boolean;
+  upload_firmware: boolean;
 }