add guide on how to install libgit2 (#13743)
add guide on how to install libgit2 (#13743)

* add guide on how to install libgit2

* Apply suggestions from code review

Co-authored-by: Klaudia Grzondziel <061b7484c464fc4e583c427a028afc8ee730f897@users.noreply.github.com>

* include comments from code review

* fix the code in step 1

* Apply suggestions from code review

Co-authored-by: Klaudia Grzondziel <061b7484c464fc4e583c427a028afc8ee730f897@users.noreply.github.com>

* add cause to the troubleshooting

* Apply suggestions from code review

Co-authored-by: Klaudia Grzondziel <061b7484c464fc4e583c427a028afc8ee730f897@users.noreply.github.com>

Co-authored-by: Klaudia Grzondziel <061b7484c464fc4e583c427a028afc8ee730f897@users.noreply.github.com>
kyma-project/kyma,kyma-project/kyma,kyma-project/kyma,kyma-project/kyma