Changes:
* Stop producing Microsoft.AspNetCore.Routing.DecisionTree.Sources. I could not find any usages outside of the Microsoft.AspNetCore.Routing assembly, so I've moved this to be a subfolder of code in the Microsoft.AspNetCore.Routing project.
* Stop building src/Routing as a submodule. Use ProjectReference instead
* Move projects from src/Routing into src/Http/Routing/ and src/Http/Routing.Abstractions/
* Update package baselines and dependencies to support building routing projects and samples
- Stop producing the 'Universe' lineup package
- Removes all PackageLineup code
- Use full msbuild on Windows
- Fix invalid reference to internal.aspnetcore.sdk in 2.1.x
- Fix shared folder references for PackageArchive task.
- #7156 part 1 of ?
- add `CompatibilityVersion.Version_3_0` and make it the default
- remove tests of old versions
- also remove `CompatibilityVersion.Version_2_x` uses outside src/Mvc
- for functional tests of legacy routing, use `MvcOptions.EnableEndpointRouting` to control behaviour
- rename `StartupWith2xCompat...` classes to `StartupWithoutEndpointRouting`
- clean up comments mentioning `[Obsolete]` `CompatibilityVersion` values
- many of the affected options will be removed in subsequent PRs but this cleanup helps when searching entire repo
- correct `<value>` comments in `ApiBehaviorOptions`
nits:
- take VS suggestions in changed files
- remove src/SiteExtensions/global.json and let file in repo root "win"
- fix a few grammar errors VS or the spell checker noticed
- move `<value>` elements before `<remarks>` for consistency
- was undoing unintentional changes and noticed the inconsistency in a couple of additional files
* Regenerate Mvc functional test baselines
- whitespace likely changed due to a recent Razor change (but there've been so many!)
* Don't trim response content in `RazorPagesTest.Page_SimpleForms_RenderAntiforgery()`
- was inconsistent with generated baseline and `Trim()` in similar tests is generally not needed or correct
* Skip test method causing remaining two src/Mvc failures
- #4417 opened to restore these tests