Since MavenCentral requires GPG signed artifacts, we'll need to configure
some things on the machine running the deployment. Specifically, these
three Gradle properties need to be set (preferably in ~/.gradle/gradle.properties)
```
signing.keyId= // Duh
signing.password= // I have absolutely no idea how this will work with HSMs
signing.secretKeyRingFile= // $HOME/.gnupg/... you know the deal
```
The BINTRAY_USER and BINTRAY_KEY variables are replaced by SONATYPE_USER
and SONATYPE_PASSWORD to better reflect their new contents.
Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>