Deprecate IfcRelConnectsPortToElement in favour of IfcRelNests only

Description of the proposal:

`IfcRelConnectsPortToElement` used to be used to connect an `IfcPort` to an `IfcDistributionElement`. Then the documentation changed and said to use `IfcRelNests` instead ... **except** when the port is dynamically connected (my interpretation of dynamic is wireless, perhaps?).

Based on [this forum thread](https://forums.buildingsmart.org/t/ifcrelconnectsporttoelement/2510/5), Thomas Liebich considers it "essentially deprecated", so I propose to officially deprecate it, and if there is a need to distinguish fixed vs dynamic ports, move that into a Pset.

If this is agreed, I can make a list of all the places to fix it in the documentation.

Describe how it contributes to the objectives set in https://github.com/buildingSMART/NextGen-IFC/wiki/Towards-a-technology-independent-IFC:

What do we win:

- One less relationship, which only had a minor difference to another relationship.
- More clarity in the sepc

What do we loose <-- can we fix this typo?

- Nothing

Schema impact:

- Smaller schema

Instance model impact:

- Smaller

Backwards compatible:

- No, a relationship disappears. Effectively IFC2x3 files will all have errors.

Automatic migration possible:

- Yes. Very easy.

Additional implications:

-
Note that not all points need to be satisfied!
Backwards compatibility and file size are not concerns.

Start with the proposal and the linked buildingSMART forum thread to resolve whether IfcRelConnectsPortToElement should be officially deprecated and how dynamic ports are treated. If accepted, inventory the affected documentation, record the IFC2x3 compatibility and migration implications, and update the documentation to consistently prefer IfcRelNests.

Written by the indexing model from the issue text.