Install review-tools directly from pip.

Review-tools from snap has moved from classic to confined. So it is
broken and fails. We cannot use it with the same trick as snapcraft.

We still install snapcraft from snap, because it is a pain to install
manually.
3 jobs for valentindavid/review-tools-pip in 20 minutes and 18 seconds (queued for 34 seconds)
Status Job ID Name Coverage
  Build
passed #243186298
aarch64
aarch64

00:18:04

passed #243186297
x86_64
amd64

00:10:15

passed #243186299
ppc64le
ppc64le

00:07:56