Review of #644

[matjack1]

Since the PR #644 was abandoned I've finished the review myself, and here it is.

mainly these things are changed/added:

• more mqtt data is send (pincode for example) and ha discovery for that added (easier to integrate in ha with alarmo, yu can use the pincode from esp-rfid for arm/disarm alarmo)
• systemname is shown on status page and in the menu under the esp-rfid-icon (makes it more easier to manage if you have more than one device)
• uptime on status page human readable see issue Improve rendering of uptime in web UI #607

[matjack1]

Thank you @pvtex for the bulk of the work here! :)