docker: Break up build commands into seperate RUN calls

I think this was from back when the Dockerfile was first being written, before the 'builder' and 'final' stages were introduced which make this former optimization attempt completely redundant

docker/azahar-room/Dockerfile

@@ -6,16 +6,16 @@ FROM opensauce04/azahar-build-environment:latest AS builder
 
 COPY . /var/azahar-src
 
-RUN mkdir builddir && cd builddir && \
-    cmake /var/azahar-src -G Ninja \
+RUN mkdir ./builddir/
+WORKDIR ./builddir/
+RUN cmake /var/azahar-src -G Ninja \
                           -DENABLE_QT=OFF \
                           -DENABLE_GDBSTUB=OFF \
                           -DENABLE_TESTS=OFF \
                           -DENABLE_ROOM=ON \
-                          -DENABLE_ROOM_STANDALONE=ON && \
-    ninja && \
-    mv bin/Release/azahar-room /usr/local/bin/ && \
-    cd .. && rm -rf builddir
+                          -DENABLE_ROOM_STANDALONE=ON
+RUN ninja
+RUN mv ./bin/Release/azahar-room /usr/local/bin/
 
 # --- Final ------------------
 FROM debian:trixie AS final