[web] Added redirects for (old) keyword docs and license.

Tutorial books contain links to the old OGS-5 keyword documentation.

netlify.toml

@@ -32,3 +32,11 @@
     yarn --ignore-engines --ignore-optional --non-interactive
     pandoc-citeproc --bib2json ../Documentation/bibliography.bib > data/bibliography.json
     hugo -b $DEPLOY_PRIME_URL"""
+
+[[redirects]]
+  from = "/help/documentation"
+  to = "https://ogs5-keywords.netlify.com"
+
+[[redirects]]
+  from = "/project/license"
+  to = "https://github.com/ufz/ogs/blob/master/LICENSE.txt"