Zigbee UI change color of last seen depending on age

[s-hadinger]

Description:

Zigbee Web UI: display in grey instead of white when last seen time exceeds one hour or one day. Don't display any value above 100 days.

Ex:

Checklist:

• The pull request is done against the latest dev branch
• Only relevant files were touched
• Only one feature/fix was added per PR and the code change compiles without warnings
• The code change is tested and works on Tasmota core ESP8266 V.2.7.4.7
• The code change is tested and works on Tasmota core ESP32 V.1.0.4.2
• I accept the CLA.

NOTE: The code change must pass CI tests. Your PR cannot be merged unless tests pass