Userland: Add support for jails

This happens in two ways:
1. LibCore now has two new methods for creating Jails and attaching
   processes to a Jail.
2. We introduce 3 new utilities - lsjails, jail-create and jails-attach,
   which list jails, create jails and attach processes to a Jail,
   respectively.

Base/usr/share/man/man1/jail-create.md

@@ -0,0 +1,20 @@
+## Name
+
+jail-create - create a new jail
+
+## Synopsis
+
+```**sh
+$ jail-create <name>
+```
+
+## Description
+
+`jail-create` creates a new jail, with a specified name
+
+## Examples
+
+```sh
+# Create jail with the name "test-jail"
+$ jail-create test-jail
+```