It would be nice and more intuitive if the webapp --listen parameter accepted a port specifier too allowing configuration of the port.
For my workflow, I thought I would contain all of git annexes dependencies inside a docker image since I'm quite comfortable with docker(and emerge on gentoo took a long time and finally failed). With an unconfigurable dynamic port though, it makes running the webapp subcommand in docker not really viable since I don't want to use docker run's port range mapping feature which will lock all those ports.
### What steps will reproduce the problem?
Dockerfile:
ARG DEBIAN_TAG=buster-slim
FROM debian:${DEBIAN_TAG}
RUN set -ex \
&& apt-get update \
&& apt-get install -y \
git \
git-annex
docker build -t git-annex:test .
docker run --rm -it git-annex:test git annex webapp --listen 0.0.0.0:8888
### What version of git-annex are you using? On what operating system?
