Add new tutorials

.gitmodules

 [submodule "files/cpp_sisso"]
 	path = files/cpp_sisso
 	url = https://gitlab.mpcdf.mpg.de/nomad-lab/cpp_sisso.git
+[submodule "tutorials/analytics-compressed-sensing"]
+	path = tutorials/analytics-compressed-sensing
+	url = https://gitlab.mpcdf.mpg.de/nomad-lab/analytics-compressed-sensing.git
+[submodule "tutorials/analytics-tetradymite-PRM2020"]
+	path = tutorials/analytics-tetradymite-PRM2020
+	url = https://gitlab.mpcdf.mpg.de/nomad-lab/analytics-tetradymite-PRM2020.ipynb.git
+[submodule "tutorials/analytics-descriptor-role"]
+	path = tutorials/analytics-descriptor-role
+	url = https://gitlab.mpcdf.mpg.de/nomad-lab/analytics-descriptor-role.git

analytics-compressed-sensing @ bf570e81

+Subproject commit bf570e818b8ca56d9b02da6e8b4e61c6392f1b41

analytics-descriptor-role @ b2c51ce7

+Subproject commit b2c51ce7a6f6d57494936639b72d5d4738ac5dcb

analytics-tetradymite-PRM2020 @ b1f7ef94

+Subproject commit b1f7ef94694ef2a668cd5e2e76c026069a541bbe