Add a couple of empty dirs and missing tool

Here we are adding a couple of empty directories (.nvm and .npm)
that will enable the use of nodejs within the images.

Also the "bc" package that is used by some bash scripts to perform
"float point" (version comparisons) operations.

Dockerfile

@@ -7,7 +7,7 @@ RUN echo "Building for ${TARGETPLATFORM}"
 
 # Install some packages that are useful within the images.
 RUN apt-get update && apt-get install -y \
-    git \
+    git bc \
 && rm -rf /var/lib/apt/lists/*
 
 # Install pickle as an easier alternative to PECL, that is not
@@ -45,7 +45,9 @@ RUN /tmp/setup/sqlsrv-extension.sh
 RUN mkdir /var/www/moodledata && chown www-data /var/www/moodledata && \
     mkdir /var/www/phpunitdata && chown www-data /var/www/phpunitdata && \
     mkdir /var/www/behatdata && chown www-data /var/www/behatdata && \
-    mkdir /var/www/behatfaildumps && chown www-data /var/www/behatfaildumps
+    mkdir /var/www/behatfaildumps && chown www-data /var/www/behatfaildumps && \
+    mkdir /var/www/.npm && chown www-data /var/www/.npm && \
+    mkdir /var/www/.nvm && chown www-data /var/www/.nvm
 
 ADD root/usr /usr