Minor fixes release:

• export: ensure applications user dir exists
• create: fix reduntant mountpoint
• create: mount host's root filesystem as whole, not single directories
• init/export: check if we're in a container earlier
• fix some typos
• improve outputs for the users
• add new tested hosts, distrobox is now tested and verified working on - OpenSUSE Leap 15 and Tubleweed - Arch - Manjaro - Fedora Silverblue 34 and 35 - EndlessOS 4.0.0 - OpenSUSE MicroOS