Add IMAP support and refactor environment configuration

- Introduced `imap_connect.py` for handling IMAP email interactions.
- Created `run.py` to manage execution based on the selected mode (IMAP or EWS).
- Updated Dockerfile and .env.dev to include necessary environment variables.
- Enhanced logging and email processing in `exchange_connect.py`.
- Added `weasyprint` and `imapclient` to requirements.

Dockerfile

@@ -1,5 +1,6 @@
 FROM python:3.10-bullseye
 
+ENV mode="EWS"
 ENV username=
 ENV password=
 ENV server="exchange.sankt-wendel.de"
@@ -61,4 +62,4 @@ COPY ./app .
 COPY *.crt /usr/local/share/ca-certificates/
 RUN update-ca-certificates
 
-CMD [ "sh","-c","/etc/init.d/cups start && python3 /usr/src/app/exchange_connect.py" ]
+CMD [ "sh","-c","/etc/init.d/cups start && python3 /usr/src/app/run.py" ]