removed API in service hub that internally play with data (options) in workspace rather than solution snapshot.

now, like other features, analyzer uses snapshot of options rather than mutable one from Workspace.

eventually we should only use OptionSet snapshot embeded in solution rather than one in workspace.

This is an automated migration of our project files to the new SDK /
PackageReference.  It is done using the tool located here:

https://github.com/jaredpar/ConvertPackageRef

don't convert metadata reference to project reference. this workspace replicates workspace in host (VS), it is a bug that it tried to convert metadata reference to project reference.

also, this sometimes caused VS to crash since if a user had circular reference by metadata reference, by converting metadata reference to project reference, we are introducing circular p2p reference in solution, and workspace crash.

now, it will get synched when remote host is first created rather than doing that on demand. so functionality change, so re-organized where things happening.

1. write logs as warning rather than error when connection is closed (basically operation cancelled)

2. build compilation concurrently for diagnostic analyzers.

added unit test

this support wasn't there before since code lens nor solution analysis requires it.

added unit test

make sure we use ordered list of document/projectIds when creating checksum
make sure we set HasAllInformation when creating projectInfo

added unit test

Ensure that all *.*proj, *.props, and *.targets files are prefixed with the xml and copyright elements

1. filter out projects that is not supported in remote host when calculating checksum
2. wrong validation on contract

unit test added

Add Razor Language Service shim for accessing the remote client

Add Razor Remote Workspace shim for getting access to the solution in
the ServiceHub process. This relies on the same set of Roslyn services
being called by the client to initialize state in the remote process.

Add overloads to the 'remote' solution service to avoid a need for IVT in
in the Razor Remote Workspace shim. Checksum is internal to Workspace.

add options back to diagnostics