removed gitmodules file and updated readme

.gitmodules

-# SPDX-FileCopyrightText: 2023 Max Planck Institute for Meteorology, Yaco authors
-#
-# SPDX-License-Identifier: BSD-3-Clause
-

README.md

@@ -8,6 +8,30 @@ SPDX-License-Identifier: BSD-3-Clause
 
 Yaco is a tool to receive data from YAC and write it to different output formats. It is designed to be easily extendible for new output formats and grids.
 
+## Build for your machine
+
+Yaco can be built out of source using the scripts provided under ${YACO_ROOT}/scripts/setup 
+In order to build yaco along with all its dependencies on levante for eg., one should do the following (preferably on an interactive node): 
+```
+mkdir build && cd build 
+../scripts/setup/levante.intel-ompi412.sh --yaco-root ..
+```
+
+The same can be done for lumi or the generic machine. 
+Currently supported compilers are: 
+```
+# tested on levante (spack load)
+openmpi@4.1.2%intel@=2021.5.0
+openmpi@4.1.5%intel@=2021.5.0
+
+# tested on lumi (module load)
+cce/16.0.1.1
+cce/17.0.1 
+
+# generic machine
+gcc-13
+```
+
 ## Configuration
 
 Yaco is configured using a yaml file that is specified at runtime and that is expected to be in the form as described in the following