Fix various issues #214, #263, #279

##### https://github.com/projectkudu/kudu/issues/279 Kudu Backend to handle ScmType env
This is to start consuming ScmType which Antares will flow to us as env vars.  In s20, kudu is enabled by default when creating sites, this variable will dictate whether the Git functionality is enabled (ScmType != None && != Tfs).

##### https://github.com/projectkudu/kudu/issues/214 Deprecate Kudu.Services.Web.AppSettings
Remove the AppSettings class by migrating the settings to the unified DeploymentSettings.  The blocklocalrequest module is configure thru web.config (private kudu will enabled it).   More classes are removed as a result.

##### https://github.com/projectkudu/kudu/issues/263 Exclude FREB logs from Dump zip file
Exclude FREB from /dump zip package.  The reason is FREB xml contains user sensitive data (Basic Auth Header).  We generally ask users to give us the zip to help with issue investigation.  We don't want user to expose this info accidentally.