executor: add proof of concept instrumentation options

[matthewfala]

POC (Do not merge)

Add proof of concept instrumentation options.

Design of actual instrumentation is more elegant.

• Abstract instruments into modular components.
• Mods components include execution modifiers like valgrind and other tools that could affect the process or run along side it like like a set of instruments nested in a metronome and beat.
• Metronome and Beat are adapters between instruments and Mods. They hit the instruments at a certain interval or frequency.

Issue #, if available:

Description of changes:

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