Cleanup saca-hub.tfvars.sample to remove variables not used.

[shannawaz]

The following variables in saca-hub.tfvars.sample is causing multiple warning messages. Please remove.

tier0_rgname = "{TIER0_RGNAME}"
tier0_vnetname = "{TIER0_VNETNAME}"
tier1_rgname = "{TIER1_RGNAME}"
tier1_vnetname = "{TIER1_VNETNAME}"
tier2_rgname = "{TIER2_RGNAME}"
tier2_vnetname = "{TIER2_VNETNAME}"

Warning: Value for undeclared variable

The root module does not declare a variable named "tier1_rgname" but a value
was found in file
"/home/shnawa/mlz/d0328/missionlz/src/core/saca-hub/saca-hub.tfvars". To use
this value, add a "variable" block to the configuration.

Using a variables file to set an undeclared variable is deprecated and will
become an error in a future release. If you wish to provide certain "global"
settings to all configurations in your organization, use TF_VAR_...
environment variables to set these instead.

[glennmusa]

This will be addressed by currently planned work. Will link to the PR when it merges to main.

[brooke-hamilton]

#228 will fix this issue. Thanks @shannawaz for the bug report. 💯