Fix the performance non-functional requirements to be less ambiguous.

[BilalM04]

This issue is a result of #3753 and #3753 (comment)

Currently, the NFR for performance is ambiguous as the language used is not specific enough. We should tighten up the language and not give the competitor as an example, but rather as the target for the requirement. The competitor can be a parameter that is provided to each example.

A proposed performance NFR structure is as follows: "The (metric) for (task) shall be within (target)% of (competitor)."
Where the items in the parenthesis are parameterized.

This issue is only present in Game Physics.