Migrate email integration artifact repositories to digiwf-core

[lmoesle]

As a software developer I want to integrate the digiwf-email-integration into the digiwf-core monorepository to simplify maintenance.

Tasks

• Add email integration artifact to the digiwf-integrations package
• Configure pom.xmls to integrated the integration into the build mechanism
• pom.xml uses versions of shared packages from the parent (root pom in the digiwf-core)
• Setup Build Pipelines for docker images (append to this file https://github.com/it-at-m/digiwf-core/blob/dev/.github/workflows/snapshot-release.yaml)
• Migrate open issues from the repository to digiwf-core
• Archive old repository

Criteria

• Integration artifact is integrated into the digiwf-core monorepo
• Integration artifact is integrated into the build pipeline
• Issues are migrated to digiwf-core
• Old repository is archived
• Repository documentation is updated