Enhance Dockerfiles

* Prevent failure when obj exists from host compile
* Enhance readability of disposed stages
* Formatting

Dockerfile

@@ -3,9 +3,8 @@ ARG DOTNET_VERSION=2
 FROM microsoft/dotnet:${DOTNET_VERSION}-sdk as builder
 WORKDIR /repo
 COPY . .
-RUN export DOTNET_CLI_TELEMETRY_OPTOUT=1 \
- && dotnet clean \
- && dotnet publish \
+ENV DOTNET_CLI_TELEMETRY_OPTOUT=1
+RUN dotnet publish \
     --configuration release \
     --output /jellyfin \
     Jellyfin.Server