Adding issue and PR templates and ros_ci workflow

[susanachl]

Description

This PR establishes the foundational repository health, community standards, and automation configurations for the dicom_to_ros repository by introducing standard GitHub issue templates, a PR template, and an automated continuous integration (CI) pipeline for ROS 2.

Type of Change

• New feature (non-breaking change which adds functionality)
• Documentation update

How Has This Been Tested?

• Verified local directory structure inside the .github/ folder.
• Checked Markdown syntax validation for issue and PR layouts.
• Confirmed workflow syntax matches the standard ros-tooling/action-ros-ci automated pipeline specification.

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Contributor Checklist:

• My code follows the ROS 2 code style guidelines for Python.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new linters/syntax warnings.
• Developer Certificate of Origin (DCO): I have signed-off every commit in this PR by adding Signed-off-by: Susana susana.chavez@ekumenlabs to the commit messages.

[gonzodepedro]

LGTM