feat: Add Gmail Catchall Labeler service with configuration and functionality

- Introduced a new Docker Compose configuration for the Gmail Catchall Labeler service.
- Implemented GmailOptions class for managing configuration settings.
- Developed GmailApiClient to interact with the Gmail API, including methods for fetching messages and managing labels.
- Created models for Gmail messages, labels, and headers.
- Added IGmailClient interface to define the contract for Gmail client implementations.
- Implemented GmailOrganizer to handle the organization of emails based on recipient addresses.
- Developed LabelNameResolver for generating label names based on local parts of email addresses.
- Created RecipientExtractor to extract local parts from email headers.
- Implemented state management with OrganizerState and StateStore for persisting state information.
- Added Worker class to manage the background processing of email organization.
- Created unit tests for GmailOrganizer, LabelNameResolver, and RecipientExtractor to ensure functionality.
- Added necessary project files and configurations for building and running the application.

Dockerfile

@@ -0,0 +1,20 @@
+FROM mcr.microsoft.com/dotnet/sdk:10.0 AS build
+WORKDIR /source
+
+COPY src/GmailCatchallLabeler/GmailCatchallLabeler.csproj src/GmailCatchallLabeler/
+RUN dotnet restore src/GmailCatchallLabeler/GmailCatchallLabeler.csproj
+
+COPY src/GmailCatchallLabeler/ src/GmailCatchallLabeler/
+RUN dotnet publish src/GmailCatchallLabeler/GmailCatchallLabeler.csproj \
+    --configuration Release \
+    --no-restore \
+    --output /app
+
+FROM mcr.microsoft.com/dotnet/aspnet:10.0 AS final
+WORKDIR /app
+RUN mkdir /data && chown "$APP_UID:$APP_UID" /data
+COPY --from=build --chown=$APP_UID:$APP_UID /app .
+USER $APP_UID
+VOLUME ["/data"]
+EXPOSE 8080
+ENTRYPOINT ["dotnet", "GmailCatchallLabeler.dll"]