chore(ci): update aks iac

[mjnagel]

Description

Modifies CI in a few ways for AKS:

• switch from azapi -> azurerm for AKS cluster creation: reduces extra provider dependency and should help fix some timing issues that intermittently cause permissions problems in CI
• changes node configuration and sizing: should be a net change from 5 nodes (2 system) -> 4 nodes (1 system) and bringing the sizes more in line with our EKS/RKE2 node sizes. Overall cost should go slightly down as well.
• fixes some deprecated items and cleans up (tflint) unused variables
• adds a few params explicitly in the init task to help with local usage

Related Issue

Related to #2196

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Other (security config, docs update, etc)