Move build jobs to hosted pools (#22)

* Move build jobs to the Hosted VS2017 pool instead of our internal pool
* Move the prepare-release-internalonly job from a team-specific pool to a shared pool with more capacity
* Remove symbol publishing from PR/CI builds since it's not necessary; do it only in release builds

build/pipelines/templates/build-single-architecture.yaml

@@ -42,12 +42,3 @@ steps:
       artifactName: drop
       pathToPublish: $(Build.BinariesDirectory)
       parallel: true
-
-  - task: PublishSymbols@2
-    displayName: Publish symbols
-    inputs:
-      symbolsFolder: $(Build.BinariesDirectory)\$(BuildConfiguration)\$(BuildPlatform)
-      searchPattern: '**/*.pdb'
-      symbolServerType: teamServices
-      treatNotIndexedAsWarning: true
-      symbolsArtifactName: $(System.teamProject)/$(Build.BuildNumber)_$(BuildPlatform)$(BuildConfiguration)