Import ESP_UniClock (upstream 1189810)

Vendored from https://github.com/gpeter62/ESP_UniClock: the sketch
source, the web UI and the libraries the ESP8266 build needs, unpacked
from the bundled zips. Adds a PlatformIO project for the ESP-12. The
source is unchanged; local changes follow as separate commits.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

firmware/uniclock/lib/NTPClient/CHANGELOG

@@ -0,0 +1,15 @@
+NTPClient 3.1.0 - 2016.05.31
+
+* Added functions for changing the timeOffset and updateInterval later. Thanks @SirUli
+
+NTPClient 3.0.0 - 2016.04.19
+
+* Constructors now require UDP instance argument, to add support for non-ESP8266 boards
+* Added optional begin API to override default local port
+* Added end API to close UDP socket
+* Changed return type of update and forceUpdate APIs to bool, and return success or failure
+* Change return type of getDay, getHours, getMinutes, and getSeconds to int
+
+Older
+
+* Changes not recorded