Add the minimal boot method to the docs

Signed-off-by: Neil Williams <neil.williams@linaro.org>
12 jobs for minimal in 8 minutes and 19 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Test
passed #23291
amd64
dispatcher-debian-10

00:02:36

passed #23289
amd64
dispatcher-debian-9

00:02:58

passed #23292
amd64
server-debian-10

00:01:59

passed #23290
amd64
server-debian-9

00:02:30

 
  Analyze
passed #23293
amd64
black

00:00:22

passed #23294
amd64
codestyle

00:00:30

passed #23295
dind amd64 allowed to fail
sast

00:01:41

 
  Build
passed #23298
amd64
amd64/pkg-debian-10

00:01:27

passed #23297
amd64
amd64/pkg-debian-9

00:01:45

passed #23296
amd64
doc

00:01:11

 
  Docker
passed #23299
dind amd64
amd64/lava-dispatcher

00:00:41

passed #23300
dind amd64
amd64/lava-server

00:01:52