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/ESPAsyncWebServer/library.properties

@@ -0,0 +1,9 @@
+name=ESP Async WebServer
+version=1.2.3
+author=Me-No-Dev
+maintainer=Me-No-Dev
+sentence=Async Web Server for ESP8266 and ESP31B
+paragraph=Async Web Server for ESP8266 and ESP31B
+category=Other
+url=https://github.com/me-no-dev/ESPAsyncWebServer
+architectures=*