[master < T570] Implement hash on mgp::Value

[imilinovic]

There was a need to use std::unordered_set and std::unordered_map with mgp::Value.
[master < Epic] PR

• Check, and update documentation if necessary
• Write E2E tests
• Compare the benchmarking results between the master branch and the Epic branch
• Provide the full content or a guide for the final git message

[master < Task] PR

• Check, and update documentation if necessary
• Provide the full content or a guide for the final git message

To keep docs changelog up to date, one more thing to do:

• Write a release note here, including added/changed clauses
  Inside _mgp.hpp added functions value_get_numeric (value of number in double) and value_is_numeric (returns if mgp_value is numeric, (int or double)).
  C++ API:
  Added std::hash for mgp::Value and all its subtypes (mgp::Map, mgp::Path, ...)
  You are able now able to use them inside hash structures like std::unordered_map and std::unordered_set.

• Tag someone from docs team in the comments

[antoniofilipovic]

Few changes and should be good to go. Fix only this what we talked about that we will copy what we need from utils/fnv.hpp inside mgp namespace

[antoniofilipovic]

All seems good now to me

[antepusic]

I think it’s all good too!

[vpavicic]

@imilinovic - a release note please! what's new/improved here?

[imilinovic]

@vpavicic Done