Maintenance release to keep up with latest Go stuff.

• Update all dependencies
• Switch from Macaron to chi + net/http
• Add request parameter validation

Everything authored by Claude Code

Update all dependencies and fix handling of TLS ALPN.
This makes certification requests to Let's Encrypt work again.

Update config example and default URLs to use v02 of the acme API.
V01 is long gone and no longer supported by Let's Encrypt.

Koni now supports generation of mobileconfig.xml files for iPads and iPhones:

https://koni.example.com/mobileconfig.xml?emailaddress=me@example.com

Ro enable complete request/response logging, set the following in koni.conf:

debug = yes