pkg/utils: add ELN as supported distro

[yselkowitz]

No description provided.

[gemini-code-assist]

Code Review

This pull request adds support for Fedora ELN to Toolbx by introducing ELN-specific utility functions, registering the "eln" distribution, and updating the documentation and tests. The reviewer noted that the host detection logic in getHostID() must be updated to check for VARIANT_ID == "eln" when ID == "fedora" to ensure Fedora ELN hosts are correctly identified and default to ELN containers instead of standard Fedora containers.

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[centosinfra-prod-github-app]

Build failed.
https://gateway-cloud-softwarefactory.apps.ocp.cloud.ci.centos.org/zuul/t/local/buildset/ec85aa64270a4c6faf391eeb10b3ab4c

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[yselkowitz]

ping @debarshiray