Use vcpkg steps from eng/common (Azure#3215)

Partial Azure/azure-sdk-tools#12291

vcpkg recently released a breaking change that caused errors in 4
different repos. Since vcpkg has spread to wider use, this PR uses a
unified vcpkg specified in `eng/common` which will make it easier to
recover from breaking changes to vcpkg in the future.

Author: danieljurek

eng/pipelines/templates/steps/vcpkg.yml

@@ -1,8 +1,5 @@
 steps:
-  - pwsh: |
-      Write-Host '##vso[task.setvariable variable=VCPKG_BINARY_SOURCES_SECRET;issecret=true;]clear;x-azcopy,https://azuresdkartifacts.blob.core.windows.net/public-vcpkg-container,read'
-      Write-Host '##vso[task.setvariable variable=X_VCPKG_ASSET_SOURCES_SECRET;issecret=true;]clear;x-azurl,https://azuresdkartifacts.blob.core.windows.net/public-vcpkg-container,,read'
-    displayName: Set vcpkg variables
+  - template: /eng/common/pipelines/templates/steps/set-vcpkg-cache-vars.yml
 
   - script: vcpkg --version
     condition: >-
@@ -12,19 +9,6 @@ steps:
       )
     displayName: vcpkg --version
 
-  - ${{if and(eq(variables['System.TeamProject'], 'internal'), ne(variables['Build.Reason'], 'PullRequest')) }}:
-    - task: AzurePowerShell@5
-      displayName: Set vcpkg write-mode cache
-      inputs:
-        ScriptType: FilePath
-        ScriptPath: eng/scripts/Set-VcpkgWriteModeCache.ps1
-        azureSubscription: Azure SDK Artifacts
-        azurePowerShellVersion: LatestVersion
-        pwsh: true
-      # This step is idempotent and can be run multiple times in cases of
-      # failure and partial execution.
-      retryCountOnTaskFailure: 3
-
   - pwsh: |
       vcpkg install
       Write-Host "##vso[task.setvariable variable=VCPKG_ROOT;]${env:VCPKG_INSTALLATION_ROOT}"