Sign the MSBuildSdkResolver dll in standard nupkg (dotnet#8648)

We were only signing the copy in the msbuild extensions layout for the
VS insertion package, but not the x-plat nupkg we produced for VS Code.

Merge pull request dotnet#8350 from livarcocc/merge_release_21_msrc

Merge release/2.1-MSRC into release/2.1

Merge pull request dotnet#8351 from livarcocc/merge_rel_110_msrc

Merge rel/1.1.0-MSRC into rel/1.1.0

Merge pull request dotnet#8150 from dotnet/johluo/2.0.4-lzma-2

Consume 2.0.4 LZMA attempt 2

Merge pull request dotnet#8124 from livarcocc/update_branding_to_212

Updating the branding of the CLI to 2.1.2

Merge pull request dotnet#8089 from livarcocc/update_core_setup_url

Changing the core setup blob url to one that does not use a CDN

Merge pull request dotnet#8021 from livarcocc/merge_1_1_0_MSRC

Merge release/1.1.0-MSRC into rel/1.1.0

Merge pull request dotnet#8016 from livarcocc/merge_15_5_msrc

Merge release/15.5-MSRC into release/15.5

Merge pull request dotnet#8017 from livarcocc/merge_2_0_0_MSRC

Merge release/2.0.0-MSRC into release/2.0.0

Merge pull request dotnet#7717 from AndyGerlicher/MSBuild.15.4.8

MSBuild 15.4.8