Update Dockerfile to include timezone and culture information (#226)

```json
"PdfGeneratorSettings": {
    "DisplayFooter": true
}
```

requires globalisation and timezone info in docker images

Altinn/app-lib-dotnet#792

Author: ivarne

src/Dockerfile

@@ -23,6 +23,10 @@ ENV ASPNETCORE_URLS=
 # -s --shell
 RUN addgroup -g 3000 dotnet && adduser -u 1000 -G dotnet -D -s /bin/false dotnet
 
+# Add globalization timezone support
+RUN apk add --no-cache icu-libs tzdata
+ENV DOTNET_SYSTEM_GLOBALIZATION_INVARIANT=false
+
 USER dotnet
 RUN mkdir /tmp/logtelemetry