Clean up, unify and expand badge usage in all READMEs

Laborious task:

Many READMEs of our projects use some badge to indicate build status.
Thes could be cleaned up, unified and possibly expanded (npm version, GitHub release version, ...).

Why are badges useful?
They provide a direct overview over some interesting data bits.
Did a test fail?
Is the latest release published to npm?

What other badges are useful?

Plugins have their badges embedded in a table for better display on the documentation website. Example: https://github.com/apache/cordova-plugin-file-transfer + https://cordova.apache.org/docs/en/latest/reference/cordova-plugin-file-transfer/