Fix eu translations

[FIX JENKINS-26977] Use project-specific check URL

Polish translations

[JENKINS-41511] Don't try to set slaveAgentPort when it is enforced

[JENKINS-34065] Deleting obsolete pinning UI

Print stack trace in logical order

For some reason, Bulgarian translations included a gratuitous newline between key and value, which core/move-l10n.groovy does not yet grok.

This reverts commit 4c1a23d9.
No longer needed as of 2527e66d.

[SECURITY-382] Be more compatible with maven-plugin