Dinov2 Semantic Segmentation Notebook Fix

[HarrisDePerceptron]

Broken dependencies for dinov2 segmentation

mmcv v2 and mmseg incompatiple with pytorch version on colab.
i have create a pull request for the notebook please look into it.

Pull request: #370
Notebook

similar issues: #277
@Celebio @syhw @nlutsenko @colesbury @pdollar

[tgolvano]

Function	Changes
init_segmentor	Renamed to init_model
inference_segmentor	Rename to inference_model

[jenniferjtli]

There are much more changes inside the codes. Backbone+head relatively easier to modify, while maskformer much more difficult because of missing Registry names (e.g Transformer sequence layer). Data transforms also need to be changed. Results nearly a hot mess, far from the demo website.