Release 5.7.0-rc to github packages

[dr0i]

Like #481.

This rc provides the new URLEncoder.
This is needed to solve metafacture/metafacture-fix#273.

Pushed to the 5.7.0-rc1 branch to make it available for testing via GitHub packages (version: 5.7.0-rc1 ; removed the -SNAPSHOT required for sonatype in the branch, see https://github.com/metafacture/metafacture-core/wiki/Maintainer-Guidelines#publish-to-githubpackages).

[dr0i]

@blackwinter and @fsteeg you may want to test.

[blackwinter]

• fix
• limetrans
• lobid-resources
• playground