Add nsswitch role, move auth roles together

[jabl]

Setting up sssd/nis/nsswitch needs to be done before e.g. slurm.

[martbhell]

Some improvements are possible here:

There are differences between the defaults in the role and on a standard EL7 nsswitch.conf. For example "passwd: files sss" is "passwd: files" in this role. This might not break anything but it would be nice to not change the default nsswitch.conf unnecessarily.

Two ways I see:

• A) Make nsswitch role not change anything by default. Fork etc. If we do it would be nice to add a backup=yes to the template task.
• B) Add variables to fgci-ansible/examples/group_vars/.. which by default would then set the nsswitch.conf to the default in EL7. And then it would be nice to ensure that the sites have merged these variables into their group_vars.

I suppose A) is much faster. What do you think?

[jabl]

Yeah, I think A) is easier.

[martbhell]

I'll do that now

[jabl]

Great, thanks!