AGW Update and deprecation cleanup

TLDR:

• updates legacy OMS settings
• adds os_type fields for Windows based node support
• allows you to add private IP listeners to the AGW definition

Allowing private IP listeners required a restructure of the agw() object in order to be able to toggle between public and private endpoints, as well as catching configuration differences between v1 and v2. Hence a breaking change semver bump.

Allow custom labels and taints

• now can add labels and taints to nodes
• fixes bug discovered when using Terraform 1.3.9 with the optional() function now that it is generally available
• bumps minimum TF version to 1.4.0

Update deprecated attributes

• replaces log with enabled_log to remain compatible with upcoming AzureRM 4.0.

Update to accommodate latest AzureRM and Terraform

Updates the following:

• removes experimental features in favor of the new stable default in Terraform 1.3
• adds configurable priority value to AGW when sku is set to WAF_v2 as required by AzureRM 3.3
• adds waf_configuration with configurable defaults when sku is set to WAF_v2

As a contrast the required minimum versions for both AzureRM and Terraform have been bumped.

v0.2.0

Initial preview.

Still missing a solution to bootstrap Flux into the deployment, but the basics are functional