`dotnet complete` should support installed global tools

### Describe the solution you'd like

It would be great if `complete` command (the one used for tab-completion in the terminals - bash, zsh or PowerShell) supported globally installed tools.

For example if I have `dotnet trace` global tool installed - it should complete that.

Or any other 3rd party tool obviously (for example I use `dotnet retest` a lot, from the authors of Moq)

We can already get the list of installed tools via `dotnet tool list -g` why not cache it somewhere?