Add validation code and test case

tests/data/namespaces/iow/links__0.xml

@@ -0,0 +1,40 @@
+
+<?xml version='1.0' encoding='utf-8'?>
+<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+<url>
+    <loc>https://geoconnex.us/iow/homepage</loc>
+    <lastmod>2023-09-01T05:34:10Z</lastmod>
+</url><url>
+    <loc>https://geoconnex.us/iow/aboutus</loc>
+    <lastmod>2023-09-01T05:34:10Z</lastmod>
+</url><url>
+    <loc>https://geoconnex.us/demo</loc>
+    <lastmod>2023-09-01T05:34:10Z</lastmod>
+</url><url>
+    <loc>https://geoconnex.us/iow/nldi</loc>
+    <lastmod>2023-09-01T05:34:10Z</lastmod>
+</url><url>
+    <loc>https://geoconnex.us/iow/nldi/demo</loc>
+    <lastmod>2023-09-01T05:34:10Z</lastmod>
+</url><url>
+    <loc>https://geoconnex.us/iow/map</loc>
+    <lastmod>2023-09-01T05:34:10Z</lastmod>
+</url><url>
+    <loc>https://geoconnex.us/iow/cr-demo</loc>
+    <lastmod>2023-09-01T05:34:10Z</lastmod>
+</url><url>
+    <loc>https://geoconnex.us/iow/tracker</loc>
+    <lastmod>2023-09-01T05:34:10Z</lastmod>
+</url><url>
+    <loc>https://geoconnex.us/iow/hyriver</loc>
+    <lastmod>2023-09-01T05:34:10Z</lastmod>
+</url><url>
+    <loc>https://geoconnex.us/iow/principles</loc>
+    <lastmod>2023-09-01T05:34:10Z</lastmod>
+</url><url>
+    <loc>https://geoconnex.us/iow/api-mockups</loc>
+    <lastmod>2023-09-01T05:34:10Z</lastmod>
+</url><url>
+    <loc>https://geoconnex.us/iow/guidance</loc>
+    <lastmod>2023-09-01T05:34:10Z</lastmod>
+</url></ns0:urlset>

tests/data/namespaces/iow/test.csv

@@ -0,0 +1,3 @@
+id, target, creator, description
+https://geoconnexus/iow/homepage, https://internetofwater.org, [email protected], Internet Of Water homepage
+https://geoconnex.us//usgs/monitoring-location/([a-zA-Z0-9_]+).*$, https://waterdata.usgs.gov/monitoring-location/$1, [email protected], USGS Monitoring Locations