refactor(filter,rules): Deprecate pe.ps.child.file.name field

[rabbitstack]

What is the purpose of this PR / why it is needed?

Introduce a new filter field ps.child.pe.file.name that is uniform with the other ps.child.* fields.

What type of change does this PR introduce?

• [x] Refactor (non-breaking change that restructures the code, while not changing the original functionality)

Any specific area of the project related to this PR?

• [x] Rule engine
• [x] Filters
• [x] Detection rules

Special notes for the reviewer:

Does this PR introduce a user-facing change?

Yes. The fields documentation needs to be updated to express the usage preference of the new filter field.