Create Scalability Benchmarks and run on a regular basis

[simongdavies]

At present there are a small number of performance benchmarks run as a part of PR validation but there are no scalability benchmarks.

We need to have some benchmarks that measure the scalability of hyperlight when a host process creates varying numbers of sandboxes and invokes functions on them concurrently.

These benchmarks should attempt to measure how hyperlight behaves in a number of dimensions, for example:

1. Different usage patterns e.g.

• Create a Sandbox, Use, Drop
• Create a Sandbox, initialize it, cache, use, return to cache

2. Different parameter types and sizes

[jsturtevant]

moved this to #593