Change BIND config to use inclusive language

[Adam Vest]

Hello,

I was noticing that the bind config as shipped with MAAS (the snap version, anyway) still uses master/slave references. The version of bind that's shipped with the MAAS 3.3 snap appears to be 9.18.12, and according to this[1], using such terminology is slated for deprecation and ultimate removal in a couple more versions.

Since the version of bind that's shipped supports primary/secondary terminology, just proposing that we update MAAS to use this terminology in the configs.

Thank you!

Current Version:
:~# snap list maas
Name Version Rev Tracking Publisher Notes
maas 3.3.4-13189-g.f88272d1e 28521 3.3/stable canonical✓ -

--
[1] https://lists.isc.org/pipermail/bind-users/2020-June/103303.html

[Anton Troyanov (troyanov)]

Hi Adam,

Thank you for the bug report.

FTR:
My guess is that to address this issue we need to:
1. Change src/provisioningserver/templates/dns/named.conf.template
2. Update tests at src/provisioningserver/utils/tests/test_isc.py