Remove https support and fix Sprint Boot properties in www/libresonic-standalnone.

HTTPS support will be removed upstream:
https://github.com/Libresonic/libresonic/issues/125#issuecomment-256227104

Sprint Boot properties use the "server" prefix. They are documented here:
https://docs.spring.io/spring-boot/docs/1.4.5.RELEASE/reference/htmlsingle/#boot-features-customizing-embedded-containers

Reported by: chronic at chronic se (Sprint Boot properties)
Reviewed by: des@
Approved by: des@