Merge branch 'fix-except-cache-problem' into vs16.10

Final branding for 16.10.0 (dotnet#6451)

Update VS version to use in optprof and RPS runs (dotnet#6443)

[main] Update dependencies from nuget/nuget.client (dotnet#6405)

NuGet.Build.Tasks
 From Version 5.9.1-rc.8 -> To Version 5.10.0-rc.7240

Co-authored-by: dotnet-maestro[bot] <dotnet-maestro[bot]@users.noreply.github.com>

updates (dotnet#6314)

Co-authored-by: Cristiano Suzuki <[email protected]>

Merge pull request dotnet#6273 from jeffkl/jeffkl/16.9-cherry-pick

Handle unsupported paths in ProjectInSolution.AbsolutePath (dotnet#6238)

On disk cache serialization (dotnet#6094)

### Context
BinaryFormater serialization of on-disk RAR cache is slow and unsecure. 
Related issue: dotnet#6057

### Changes Made
Serialization changed to use custom binary format by using existing `ITranslatable` 

### Testing
Unit testing
Manual testing
- Roslyn repo rebuild + incremental build

[vs16.9] NuGet Feed Update (dotnet#6136)

Co-authored-by: Matt Mitchell <[email protected]>
Co-authored-by: Ben Villalobos <[email protected]>

Loc updates (dotnet#6102)

Co-authored-by: Cristiano Suzuki <[email protected]>

Update dependencies from https://github.com/dotnet/arcade build 20201…

…130.3 (dotnet#5961)

[vs16.8] Update dependencies from dotnet/arcade