add docs

docs/20_Checks/check_reboot_required.md

+# Check Reboot required
+
+## Introduction
+
+Check if a reboot is required.
+It works for Centos and Debian/ Ubuntu.
+
+If the reboot is required:
+
+* On Centos it shows the kernel number that will be installed,
+* On Debian/ Ubuntu it shows the packages that require the reboot,
+
+## Syntax
+
+`$ check_reboot_required [-h]`
+
+### Parameters
+
+```text
+OPTIONS:
+
+    -h or --help   show this help.
+
+PARAMETERS:
+
+    None
+```
+
+## Examples
+
+`check_cronstatus`
+    The Check of cronjobs with the default loction does not require any parameter
+
+`check_cronstatus /usr/share/cronwrapper/cronstatus.sh`
+    The Check of cronjobs with custom loction.