ci: configure dependabot security updates

[a-klos]

This pull request updates the .github/dependabot.yml configuration to expand and improve dependency update management for both Python and npm projects. The key changes include supporting multiple directories for dependency updates, introducing security update grouping, and adding npm ecosystem support.

Dependency management improvements:

• Expanded Python dependency updates to cover multiple directories, including various libs and services subfolders.
• Added npm ecosystem support, enabling dependency updates for the root project and selected frontend-related directories.

Security and configuration enhancements:

• Introduced grouping for security updates for both Python and npm dependencies, allowing security-related updates to be managed separately.
• Set open-pull-requests-limit to 0 for both Python and npm, effectively disabling automatic PR creation for dependency updates unless manually triggered.