Depth V2 - Combined PR with @reallybigname on dramatic depth changes

[hithereai]

This PR does a few things:

1. Re-write of the entire depth file and related code, we now have a much more simplified code that is split into files like depth_leres, depth_zoe etc. Main depth logic is handled in depth.py.
2. Removed adabins calls from render.py, all handled in depth.py now as it was stupid from the beginning.
3. Added a complete new animation-depth-related functions by RBN that handle pure/ single depth model estimations - we now have those options under 'Depth Algorithm' instead of the old "Use Zoe Depth" Bool param: Midas+AdaBins and Zoe+Adabins invoke a legacy/compatibility mode - so users can recreate old videos. It's literally working as our current main branch. The other options will invoke the new code that handles single depth models - much better than our legacy mode in terms of... anything. Including sticking/freezing of the animation movement and varying-strength zooms where your zoom is set to a fixed value. We also got a new, much better midas model in that solo mode, LeReS, and pure AdaBins mode too (!).
4. Fixed --no-half cmd flags related issues
5. Fixed medvran and lowvram; medvram doesn't make a big difference, while lowvram does.
6. Keep in vram should work with all modes.
7. New depth changes are also reflected in a new updated version of deprecation_utils.py. This is how it looks when you load a file with use_zoe_depth=False (it will set depth alg to zoe+adabins (old) if use_zoe_depth is True in the setting file):

Thanks to @reallybigname - a huge part of this pr is made by him.

Closes https://github.com/deforum-art/deforum-for-automatic1111-webui/issues/639

~~Tiny todo list: Pop a note in ui about LeRes not for commercial use. And add a hint too.~~