Allow multiple circuits to be generated for a program with multiple operations

If I click 'Circuit' code lens near an operation I get a circuit for it. If I select command 'Q#: Show circuit' it would draw a circuit for the entry point.
When I'm developing, I would like to see **individual circuits for every operation in a file**. I may not even have an entry point yet. And I may have some operations that will fail to generate a circuit, I don't want those to block the rest.
Make 'Q#: Show circuit' show circuit for every operation in a file. Maybe add a separate command to show it for the entry point.

Start with the existing Q#: Show circuit command and the Circuit code lens behavior described in the issue. Trace how circuits are generated for an operation versus an entry point, then define completion as showing each operation's circuit independently while allowing failures in one operation without blocking the others.

Written by the indexing model from the issue text.