Remove distro specific run lines when converting

[jasonbishay]

I see a lot of dockerfiles with these types of RUN statements:

# Generate the APT cache
# ENV DEBIAN_FRONTEND=noninteractive

# Add proxy
RUN echo deb [trusted=yes] https://<host>/repository/apt-proxy-12/ bookworm main contrib non-free > /etc/apt/sources.list
RUN echo deb-src [trusted=yes] https://<host>/repository/apt-proxy-12/ bookworm main contrib non-free >> /etc/apt/sources.list

RUN echo deb [trusted=yes] https://<host>/repository/apt-proxy-12/ bookworm-updates main contrib non-free >> /etc/apt/sources.list
RUN echo deb-src [trusted=yes] https://<host>/repository/apt-proxy-12/ bookworm-updates main contrib non-free >> /etc/apt/sources.list

RUN echo deb [trusted=yes] https://<host>/repository/apt-proxy-12/ bookworm-proposed-updates main contrib non-free >> /etc/apt/sources.list
RUN echo deb-src [trusted=yes] https://<host>/repository/apt-proxy-12/ bookworm-proposed-updates main contrib non-free >> /etc/apt/sources.list

It would be nice if DFC could recognize these and either comment them out or remove them