docs: 📝 add CITATION.cff (#42)

# Description

Closes #31

This PR needs a quick review.

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Co-authored-by: martonvago <57952344+martonvago@users.noreply.github.com>

Author: lwjohnst86

CITATION.cff

@@ -0,0 +1,31 @@
+title: "Template Data Package: An opinionated setup for making FAIR and structured data using Seedcase Python packages"
+abstract: "A template for making a Git repository that follows strongly opinionated practices for building and managing a data package. These practices include using Seedcase Python packages, such as Seedcase Sprout, and the Frictionless Data Package standard."
+authors:
+  - family-names: Johnston
+    given-names: Luke William
+    orcid: "https://orcid.org/0000-0003-4169-2616"
+    affiliation: "Steno Diabetes Center Aarhus"
+  - family-names: Brødbæk
+    given-names: Signe Kirk
+    affiliation: "Steno Diabetes Center Aarhus"
+  - family-names: Beicher
+    given-names: Kristiane
+    affiliation: "Steno Diabetes Center Aarhus"
+  - family-names: Vago
+    given-names: Marton
+    affiliation: "Steno Diabetes Center Aarhus"
+cff-version: 1.2.0
+# doi:
+keywords:
+  - "template repository"
+  - "template project"
+  - "template data package"
+  - "data engineering"
+  - "data infrastructure"
+  - "data package"
+  - "frictionless data"
+  - "FAIR data"
+license: MIT
+message: "If you use this software, please cite it using these metadata."
+repository-code: "https://github.com/seedcase-project/template-data-package"
+url: "https://template-data-package.seedcase-project.org"