[web] Added Ubuntu gcc install instructions.

web/content/docs/devguide/getting-started/prerequisites.pandoc

@@ -31,7 +31,13 @@ As we use lots of features of the C++17-standard we support **Visual Studio {{<
 :::
 
 ::: {.linux}
-If you have a recent linux distribution you should also have a recent gcc. Please check that you have at least **gcc {{< dataFile "versions.minimum_version.gcc" >}}**:
+On Debian-based (e.g. Ubuntu) you need to install the `build-essential`-package (which contains the `gcc`-compiler and the `make`-tool):
+
+```bash
+$ sudo apt install build-essential
+```
+
+You need to have at least **gcc {{< dataFile "versions.minimum_version.gcc" >}}**:
 
 ```bash
 $ gcc --version