SignTool functionality complete

[jcagme]

Last set of Signing issues required in Arcade so we can call Signing to be complete

Recently Triaged Issues

All issues in this section should be triaged by the v-team into one of their business objectives or features.

• [x] https://github.com/dotnet/arcade/issues/1000
• [x] https://github.com/dotnet/arcade/issues/1295
• [x] https://github.com/dotnet/arcade/issues/1919
• [x] https://github.com/dotnet/arcade/issues/1494
• [x] https://github.com/dotnet/arcade/issues/1957
• [x] https://github.com/dotnet/arcade/issues/1370
• [x] https://github.com/dotnet/arcade/issues/2177
• [x] https://github.com/dotnet/arcade/issues/2283
• [x] https://github.com/dotnet/arcade/issues/2852
• [x] https://github.com/dotnet/arcade/issues/2888
• [x] https://github.com/dotnet/arcade/issues/2915
• [ ] https://github.com/dotnet/arcade/issues/412
• [ ] https://github.com/dotnet/arcade/issues/3651
• [ ] https://github.com/dotnet/arcade/issues/3762
• [ ] https://github.com/dotnet/arcade/issues/5234
• [ ] https://github.com/dotnet/arcade/issues/5939
• [ ] https://github.com/dotnet/arcade/issues/7621
• [x] https://github.com/dotnet/arcade/issues/7945