refactor(module/appgw): Refactor module Application Gateway and adjust examples

[sebastianczech]

Description

PR delivers changes for Application Gateway:

• README.md adjusted to new style with additional header file
• minimum Terraform version set to 1.3
• refactor variables:
  • descriptions
  • types with optionals
  • default values
  • validations
• simplify main.tf by removing not required try
• remove name generation logic from the module

Motivation and Context

#307 , #325

How Has This Been Tested?

I checked that module using example included in PR.

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist

• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes if appropriate.
• All new and existing tests passed.

[sebastianczech]

/help

ChatOPS built in help:

Currently supported commands include:

• /sca - run all SCA tests via pre-commit
• /validate - run terraform validate
• /plan - plan the infrastructure (only examples)
• /apply - deploy the infrastructure and destroy afterwards (only examples)
• /idempotence - test idempotence: deploy, plan and destroy afterwards (only examples).

The 1^st command does not take arguments, the remaining take two:

• paths - a space delimitied list of module paths
• tf_version - (optional, defaults to the latest available) a space delimited list of Terraform versions to test the infrastrucure against.

Examples:

# run idempotence tests on listed modules with Terraform versions: 1.2 (latest patch available), 1.4 (latest patch available), 1.5.4.
/idempotence paths="examples/common_vmseries examples/panorama_standalone" tf_version="1.2 1.4 1.5.4"

# run validation tests with the latest available Terraform version on listed modules.
/validate paths="modules/vmseries modules/vnet examples/dedicated_vmseries"

[sebastianczech]

/plan paths="examples/common_vmseries examples/common_vmseries_and_autoscale examples/dedicated_vmseries examples/dedicated_vmseries_and_autoscale examples/virtual_network_gateway examples/appgw"

Testing job ID: 6584100272
Job result: FAILURE

[acelebanski]

Deploying Application Gateway in WAFv2 SKU will fail. Adding this block to module's main.tf should solve the issue:

  waf_configuration {
    enabled          = var.waf_enabled
    firewall_mode    = "Detection"
    rule_set_type    = "OWASP"
    rule_set_version = "3.2"
  }

[sebastianczech]

Deploying Application Gateway in WAFv2 SKU will fail. Adding this block to module's main.tf should solve the issue:

  waf_configuration {
    enabled          = var.waf_enabled
    firewall_mode    = "Detection"
    rule_set_type    = "OWASP"
    rule_set_version = "3.2"
  }

Yes, thank you for feedback. I added support for WAF in Application Gateway: f9c1b6f

[FoSix]

just some small comments