a3016a8537
This removes most of the web-specific info to a separate extension so that it can have web-related things co-located with it. The analyzers/codefixers are not self-contained, but that may require a bit more thinking as we distribute them. This is a first step towards organizing extensions by technology areas.
The resulting output looks like this:
```
upgrade-assistant
|- Microsoft.DotNet.UpgradeAssistant.Cli.dll
|- ....
|- extensions
|- default
|- [files]
|- web
|- [files]
```
|
||
|---|---|---|
| .. | ||
| TestAssets | ||
| Microsoft.DotNet.UpgradeAssistant.Abstractions.Tests.csproj | ||
| ProjectExtensionsTests.cs | ||
| TargetFrameworkMonikerTests.cs | ||