Fix docs formatting

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>

Update docs

Fix etcd cert generation for calico-rr role

Link docs to README, update README with recent info.
Update comparsions, add kubeadm vs kargo.
Better describe variables precedence UX impact.

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>

Fix docker dns host scenario with no search domains

Fixes scenario where docker-dns.conf tries to create an empty
search entry

Set latest stable versions for Calico images

"etcd_node_cert_data" variable is undefinded for "calico-rr" role.
This patch adds "calico-rr" nodes to task where "etcd_node_cert_data"
variable is registered.

Change version for calico images to v1.0.0. Also bump versions for
CNI and policy controller.

Also removing images repo and tag duplication from netchecker role

Implement "dockerd --dns-xxx" based dns mode

remove assertion for family not being CoreOS

Also update reset.yml to do more dns/network related cleanup.

[WIP] Better fix for different CoreOS os family facts

Non preempt GCE instances for CI

Revert preemptible GCE instances for CI as they are too
much of UNREACHABLE. Later we could return to them after
figured out how to mitigate preepted instances with
automated CI retries.

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>

Rename CoreOS fact

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>

Minor fix to rkt version in group vars

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>

rkt support for control plane ( etcd + kubelet )

Fix pipeline premoderation/unit-tests

Do not run unit-tests for master merges.
Fix the permissive "null" user.

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>

Do not auto-trigger gitlab CI pipeline on PRs

For security and resources utilization reasons, do not auto-start CI
for opened/updated PRs.

A member of the kubernetes-incubator github org has first to approve
that the PR is reasonable to test by putting the "ci check this" into
the PR's comments.

If approved that way, the CI pipeline starts as always. Only the 1st step
of the pipeline is premoderatied, the rest will follow each over on
success.

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>

Issue template proposal

Fix cert paths for flannel/calico policy apps

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>

Upgrade docker version and do some cleanups for unsupported distros/docker versions

Comment cloud providers private networks use cases

README: changed minimal ansible version