Switch to gitVersion and semantic versioning, closes #86 closes #87

Also add Jacoco Plugin to generate code coverage files.

Fix previous attempt of supporting no rdirect URL, implements #71

Fix previous attempt of supporting no rdirect URL, implements #71

Evaluate redirect URI lazily, implements #69

Evaluating the redirect URI of BasicOAuth2Client lazily allows passing `null`without breaking non-interactive grant types.

Support URI redirect uris.

In the past redirect URIs we preovides as `java.net.URI` values. A few commits back we switched to `org.dmfs.rfc3986.Uri`. However, for convenience (and backwards compatibility) it would be good to provide the old constructor as a secondary constructor.