Add metadata tags for each pillar

[BernieWhite]

This update adds a new tag Azure.WAF/pillar to each rule which is set to the WAF pillar.

Why are we doing this:

• This will allow customers to create WAF pillar specific baselines.
• PSRule for Azure intends to ship a managed quarterly baseline containing only security rules. Add baseline for Security pillar rules #1633
• Improve the ability to provide PSRule for Azure recommendations in other languages.

To make this happen we will be updating all rules with this tag starting with the Security pillar.

Longer term we expect to remove the existing annotation for pillar. However in the short term both tag and annotation will exist.

Syntax:

Azure.WAF/pillar: 'Security'

For example, in YAML:

---
# Synopsis: Internet accessible Application Gateways should use protect endpoints with WAF.
apiVersion: github.com/microsoft/PSRule/v1
kind: Rule
metadata:
  name: Azure.AppGw.UseWAF
  ref: AZR-000063
  tags:
    release: 'GA'
    ruleSet: '2020_06'
    Azure.WAF/pillar: 'Security'
  labels:
    Azure.ASB.v3/control: 'NS-6'
spec:
  with:
  - Azure.IsAppGwPublic
  condition:
    field: properties.sku.tier
    in:
    - WAF
    - WAF_v2

For example in PowerShell:

# Synopsis: App Service should reject TLS versions older then 1.2.
Rule 'Azure.AppService.MinTLS' -Ref 'AZR-000073' -Type 'Microsoft.Web/sites', 'Microsoft.Web/sites/slots' -Tag @{ release = 'GA'; ruleSet = '2020_06'; 'Azure.WAF/pillar' = 'Security'; } -Labels @{ 'Azure.ASB.v3/control' = 'DP-3' } {
    $siteConfigs = @(GetWebSiteConfig);
    if ($siteConfigs.Length -eq 0) {
        return $Assert.
            HasFieldValue($TargetObject, 'properties.siteConfig.minTlsVersion', '1.2').
            ReasonFrom('properties.siteConfig.minTlsVersion', $LocalizedData.MinTLSVersion, $TargetObject.properties.siteConfig.minTlsVersion);
    }
    foreach ($siteConfig in $siteConfigs) {
        $path = $siteConfig._PSRule.path;
        $Assert.
            HasFieldValue($siteConfig, 'properties.minTlsVersion', '1.2').
            ReasonFrom('properties.minTlsVersion', $LocalizedData.MinTLSVersion, $siteConfig.properties.minTlsVersion).PathPrefix($path);
    }
}

Some of this work is already complete related to #1610