Remove required tenant prompt when initializing (CASMPET-6649)

[bklei]

Summary and Scope

Change --tenant argument to be optional to prevent BW incompatible change for non-interactive use cases.

Issues and Related PRs

• https://jira-pro.it.hpe.com:8443/browse/CASMPET-6649

Testing

Tested on ashton:

ncn-m003:~/.config/cray/configurations # cray init --hostname https://api-gw-service-nmn.local
Overwrite configuration file at: /root/.config/cray/configurations/default ? [y/N]: y
Username: vshasta
Password:
Success!

Initialization complete.
ncn-m003:~/.config/cray/configurations # cat default
[core]
hostname = "https://api-gw-service-nmn.local"
tenant = ""

[auth.login]
username = "vshasta"

ncn-m003:~/.config/cray/configurations # cray init --hostname https://api-gw-service-nmn.local --tenant vcluster-blue
Overwrite configuration file at: /root/.config/cray/configurations/default ? [y/N]: y
Username: vshasta
Password:
Success!

Initialization complete.

ncn-m003:~/.config/cray/configurations # cat default
[core]
hostname = "https://api-gw-service-nmn.local"
tenant = "vcluster-blue"

[auth.login]
username = "vshasta"

Was a fresh Install tested? N
Was an Upgrade tested? N - N/A
Was a Downgrade tested? N - N/A
If schema changes were part of this change, how were those handled in your upgrade/downgrade testing? N/A

Risks and Mitigations

Low

Requires:

• Nothing