initial version of SQIsign

Co-authored-by: Jorge Chavez-Saab <jorgechavezsaab@gmail.com>
Co-authored-by: Maria Corte-Real Santos <36373796+mariascrs@users.noreply.github.com>
Co-authored-by: Luca De Feo <github@defeo.lu>
Co-authored-by: Jonathan Komada Eriksen <jonathan.eriksen97@gmail.com>
Co-authored-by: Basil Hess <bhe@zurich.ibm.com>
Co-authored-by: Antonin Leroux <18654258+tonioecto@users.noreply.github.com>
Co-authored-by: Patrick Longa <plonga@microsoft.com>
Co-authored-by: Lorenz Panny <lorenz@yx7.cc>
Co-authored-by: Francisco Rodríguez-Henríquez <francisco.rodriguez@tii.ae>
Co-authored-by: Sina Schaeffler <108983332+syndrakon@users.noreply.github.com>
Co-authored-by: Benjamin Wesolowski <19474926+Calodeon@users.noreply.github.com>

.astylerc

@@ -0,0 +1,16 @@
+# find include src test -name '*.[ch]' | xargs astyle --options=.astylerc
+--style=google 
+--indent=spaces
+#--indent-preproc-define
+#--indent-preproc-cond
+--pad-oper 
+--pad-comma 
+--pad-header
+#--unpad-paren 
+--align-pointer=name 
+--add-braces 
+--convert-tabs
+--mode=c 
+# disable backup files
+--suffix=none
+--lineend=linux