add instr-fs and decide on its configuration

[trentm]

We should add instr-fs as an option at least for the user to enable.

However, it is debatable if this should be enabled by default. Many getting started guides suggest disabling instr-fs or suggest using requireParentSpan: false. (I have not tested the requireParentSpan: false usage to see if that helps deal with the "many fs spans during startup".)

open-telemetry/opentelemetry-js-contrib#1344 is an old (closed by stalebot) discussion around considering disabling instr-fs by default.

[david-luna]

Upstream has decided to disable it by default in @opentelemetry/auto-instrumenations-node
ref: open-telemetry/opentelemetry-js-contrib#2467