Add 2 new parameters to the code gen target

[m-nash]

To support this issue Azure/azure-sdk-tools#6187 we need to add 2 new parameters to the code gen target. Both flags are optional and default to false.

Depends on this getting merged first Azure/azure-sdk-tools#6197

• /p:SaveInputs=true : This will replace the old cleanup: false that we used to put in the tsp-location.yaml and will not only keep the TempTypeSpecFiles directory around but also forward the flag to the emitter so that the cadl.json and configuration.json are kept also.
• /p:SkipSync=true : This flag allows us to continue to run the dotnet build command to regen after making local changes to the TempTypeSpecFiles directory without replacing our local changes and without needing to copy and paste the tsp compile command from the command line

[m-nash]

Waiting for this Azure/azure-sdk-tools#6197 to merge then I will run regen preview to verify no issues.