Add Dense Prediction Transformer implementation

[codecov-commenter]

Codecov Report

Merging #55 (ddecc6e) into main (1ada247) will not change coverage. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##              main       #55    +/-   ##
==========================================
  Coverage   100.00%   100.00%            
==========================================
  Files           50        52     +2     
  Lines         1202      1440   +238     
==========================================
+ Hits          1202      1440   +238     

Impacted Files	Coverage Δ
vformer/encoder/embedding/pos_embedding.py	100.00% <100.00%> (ø)
vformer/models/dense/__init__.py	100.00% <100.00%> (ø)
vformer/models/dense/dpt.py	100.00% <100.00%> (ø)
vformer/utils/__init__.py	100.00% <100.00%> (ø)
vformer/utils/dpt_utils.py	100.00% <100.00%> (ø)

[abhi-glitchhg]

I had to copy few files from #56 and #57 to resolve conflicts