Add guardrails to GPG keys; Fix impl-jackson module

[ricardozanini]

Many thanks for submitting your Pull Request ❤️!

What this PR does / why we need it:
When releasing we were getting:

Error: [ERROR] Failed to execute goal on project serverlessworkflow-impl-jackson-jwt: Could not resolve dependencies for project io.serverlessworkflow:serverlessworkflow-impl-jackson-jwt:jar:7.3.0.Final
Error: [ERROR] dependency: io.serverlessworkflow:serverlessworkflow-impl-jackson:jar:7.3.0.Final (compile)
Error: [ERROR] 	Could not find artifact io.serverlessworkflow:serverlessworkflow-impl-jackson:jar:7.3.0.Final in central (https://repo.maven.apache.org/maven2)
Error: [ERROR] -> [Help 1]
Error: [ERROR] 
Error: [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
Error: [ERROR] Re-run Maven using the -X switch to enable full debug logging.
Error: [ERROR] 
Error: [ERROR] For more information about the errors and possible solutions, please read the following articles:
Error: [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/DependencyResolutionException
Error: [ERROR] 
Error: [ERROR] After correcting the problems, you can resume the build with the command
Error: [ERROR]   mvn <args> -rf :serverlessworkflow-impl-jackson-jwt

This is because impl-jackson was a POM, not a JAR, but was still being imported as a JAR by submodules.

In the future, we can introduce starters packages a lá SpringBoot for other bundles we plan to distribute.

Special notes for reviewers:
Need this to release.

Additional information (if needed):
Additionally, we add a small guardrail for the release process to check our GPG keys. It was failing before because the keys had expired.

[fjtirado]

For the Jackson issue, I prefer the alternative I provided on #906. Do not generate a fake jar, but just use <type>pom</type> when using the dependency.