Fix hanging on tests failing

Tee hanging when `go test` exit with non-zero code.
Fixes #5672
Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Adding the FAQ back

Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)
Make sure dev/fuse is created in container

Fixes #5849

If the host system does not have fuse enabled in the kernel config we
will ignore the is not exist errors when trying to copy the device node
from the host system into the container.
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
add unprivilegeduser via the Dockerfile

This changes the test TestBuildWithInaccessibleFilesInContext to not
add the user 'unprivilegeduser' and add it via the Dockerfile instead.

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Merge pull request #5914 from unclejack/fix_unprivileged_user_creation

add unprivilegeduser via the Dockerfile
starts by removing the name from the graph db

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
Merge pull request #5913 from crosbymichael/fuse

Make sure dev/fuse is created in container
Merge pull request #5915 from vieux/start_remove_link

starts by removing the name from the graph db
Merge pull request #5890 from LK4D4/fix_tee_hanging_on_test_fails_#5672

Fix hanging on tests failing
Merge pull request #5905 from jamtur01/faq

Adding the FAQ back