Add lines for local testing into the buildbot docker files

.buildbot/appimage/Dockerfile

@@ -24,3 +24,5 @@ RUN wget -qO appimage-builder-x86_64.AppImage \
     https://github.com/AppImageCrafters/appimage-builder/releases/download/v1.1.0/appimage-builder-1.1.0-x86_64.AppImage
 
 ADD . .
+
+CMD .buildbot/tox-bionic/build.sh

.buildbot/tox-bionic/Dockerfile

@@ -20,3 +20,7 @@ RUN python3.8 -m pip install --upgrade pip tox virtualenv
 ENV LANG en_US.UTF-8
 ENV LANGUAGE en_US:en
 ENV LC_ALL en_US.UTF-8
+
+ADD . .
+
+CMD .buildbot/tox-bionic/test.sh

.buildbot/tox-focal/Dockerfile

@@ -13,3 +13,5 @@ RUN apt-get install -yq --no-install-suggests --no-install-recommends \
 RUN python3.9 -m pip install --upgrade pip tox virtualenv
 
 ADD . .
+
+CMD .buildbot/tox-focal/test.sh

.buildbot/tox-jammy/Dockerfile

@@ -10,3 +10,7 @@ RUN apt-get install -yq --no-install-suggests --no-install-recommends \
     python3-dev python3-pip language-pack-en qt5dxcb-plugin tor xvfb
 
 RUN pip install tox
+
+ADD . .
+
+CMD .buildbot/tox-jammy/test.sh