Resolve "Subsite: Software Engineering Consulting Manual"

Closes #350 (closed)

• consulting.html to consulting.md (not feasible)
• Create a specific folder for consulting /consulting-materials/handbook/
• Add link in an existing/non-existing page
• Add /consulting-materials/index.md with some content (if not done on the initial page before) (no extra page required)
• Mark each folder with at least a file .gitkeep
• Adjust fetch_external_content.sh to include the external build *.html site
• Add /consulting-handbook/ to include .gitignore

services/software/consulting.html

@@ -113,7 +113,7 @@ excerpt: >-
 
 <p>
     For a more in-depth look at the consulting process, please have a look at our 
-    <a href={{ "consulting-materials/handbook/" | relative_url }}"><b>HIFIS Consulting Handbook</b></a>.
+    <a href={{ "consulting-materials/handbook/" | relative_url }}><b>HIFIS Consulting Handbook</b></a>.
     It provides information on the process and the corresponding services we use for successfull consultation.
 </p>
 
@@ -131,3 +131,4 @@ excerpt: >-
 <p>
     If anything goes wrong during the process, feel free to <a href="mailto:{{site.contact_mail}}">email us</a> directly.
 </p>
+