Make this library multi-platform

[oxisto]

Since most (if not all) of our dependencies are pure Kotlin, we could see how compatible we are with a Multiplatform build. This might open up interesting options to integrate this library into other native settings.

• Do not use OffsetDateTime -> maybe Kotlinx.datetime?
• Do not use URI -> this might be tricky

A first step could be to move all jvm-only things into jvmMain and then slowly move things into commonMain.