Implemented Danswer versioning system. (#649)

* Web & API server versioning system. Displayed on UI.

* Remove some debugging code.

* Integrated backend version into GitHub Action & Docker build workflow using env variables.

* Fixed web container environment variable name.

* Revise Dockerfiles for GitHub Actions workflow.

* Added system information page to admin panel with version info. Updated github workflows to include tagged version, and corresponding changes in the dockerfiles and codebases for web&backend to use env variables if present. Changed to 'dev' naming scheme if no env var is present to indicate local setup. Removed version from admin panel header.

* Added missing systeminfo dir to remote repo.

backend/Dockerfile

@@ -1,5 +1,12 @@
 FROM python:3.11.4-slim-bookworm
 
+# Default DANSWER_VERSION build argument set here. 
+# This can be overridden by passing in a build arg, typically from GitHub Actions.
+ARG DANSWER_VERSION=0.1.0
+# Then passed to the container environment.
+ENV DANSWER_VERSION=${DANSWER_VERSION}
+
+
 # Install system dependencies
 RUN apt-get update && \
     apt-get install -y git cmake pkg-config libprotobuf-c-dev protobuf-compiler \