[REVIEW] fix local vert and offset calculation

[Iroy30]

--> Fixed the local data calculation to get correct csr/csc representation of distributed graph.
--> Fixed personalization bug when renumber=True
--> Removed snmg files
--> Updated API and renaming of dask-cudf Dataframe
--> Updated Comms and added docs

[codecov-commenter]

Codecov Report

Merging #1017 into branch-0.15 will decrease coverage by 0.00%.
The diff coverage is 76.47%.

@@               Coverage Diff               @@
##           branch-0.15    #1017      +/-   ##
===============================================
- Coverage        67.89%   67.89%   -0.01%     
===============================================
  Files               57       55       -2     
  Lines             2031     2034       +3     
===============================================
+ Hits              1379     1381       +2     
- Misses             652      653       +1     

Impacted Files	Coverage Δ
python/cugraph/dask/mg_pagerank/pagerank.py	96.00% <ø> (ø)
python/cugraph/comms/comms.py	83.33% <75.00%> (ø)
python/cugraph/dask/common/input_utils.py	96.90% <75.00%> (ø)
python/cugraph/structure/graph.py	75.64% <80.00%> (-0.79%)	⬇️
python/cugraph/_version.py	44.80% <0.00%> (+0.39%)	⬆️

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[afender]

Just need to fix conflicts