[PSUPCLPL-9776] change default podSubnet for IPv6

[n549]

Description

In case of ipv6 usage kubernetes uses /64 for pod subnet per node by default. Accordingly pod subnet for the cluster should be not less than pod subnet per node. Current default podSubnet is fd02::/80 which leads to error during installation procedure.
There are flags for controller-manager which allow to reduce this network but kubeadm fails to run some command during cluster installation. So it's better to use the default kubernetes settings.

Fixes # (issue)
PSUPCLPL-9776

Solution

• change mask for ipv6 default podSubnet from /80 to /48.
• adjust default setting for CALICO_ROUTER_ID so it would be hash in case of ipv6 podSubnet (this setting is already described in the installation documentation, but making it default helps to avoid errors in case users don't read all the documentation).

How to apply

Deploy cluster in ipv6 network environment.

Test Cases

1. Deploy cluster in ipv6 network environment.
   Check that no errors about podSubnet appear during the installation and calico is up&running.

2. Deploy cluster with default calico settings in ipv4 environment.
   Check that calico-node pods are up&running.

Checklist

• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• Integration CI passed
• Unit tests. If Yes list of new/changed tests with brief description
• There is no merge conflicts

Unit tests

Indicate new or changed unit tests and what they do, if any.

Reviewers

@koryaga @iLeonidze @Zaborin @alexarefev @Yaroslav-Lahtachev @dmyar21