add a function to put filter into a exact position

[summeroff]

Description

Add a new function.
Function will put a filter into an exact position.

Motivation and Context

Existing function obs_source_filter_set_order was limited in a way what it only move filter up or down by single position.

How Has This Been Tested?

There was also added new function in osn what will use it.
And new test for that function.

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the streamlabs branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.