Webdav recursive dirs

See Andre's note - if the project folder doesn't already exist (e.g. a new project) the pipeline fails to push the docs.

Plan: a dav_recursive_mkdir function in functions.sh that walks the path segments of the provided project folder path and makes sure all the parent directories exist. When the web server is brought back up I'm going to look into how curl -X MKCOL (mkdir for webdav) behaves when the directory already exists, then use dav_mkdir() with or without curl -X PROPFIND (PROPFIND is like ls for webdav).

gitlab/before_docs.sh

@@ -3,6 +3,12 @@
 
 source $(dirname ${0})/functions.sh
 
+# if the docs will be uploaded to at least one place,
+# make sure that the project folder will be available
+if [[ ${#DOC_UPLOADS[@]} -gt 0 ]]; then
+  dav_recursive_mkdir "${DOC_SERVER_PREFIX}"
+fi
+
 # Deletes all existing dav folders that will be overwritten
 for k in "${DOC_UPLOADS[@]}"; do
   dav_delete "${k}"