[fastify] Allow more instrumentation options like ignoreLayersType

[ValentinLevier]

Is your feature request related to a problem? Please describe

I would like to ignore specific fastify spans created by the library (e.g: middleware or request_handler) because I do not have any needs to keep them. Hence, it is just polluting my traces right now.

Describe the solution you'd like to see

I would like to have more Instrumentation options on fastify library like the Express one.
More specifically I would like to have the ignoreLayersType option.

Describe alternatives you've considered

Unfortunately I didn't find any good workaround right now.