Provides a link to the list of encoding in Python

Better links

Added link to standard encodings in io html documentation

Removed link to Python2 documentations and left link to Python3 only
Merge pull request #8125 from dxshank/dev-update-read-csv-docs

DOC: Link to Python standard encodings from read_csv documentation
DOC: v0.15.0 for GH8226
DOC: created advanced indexing section
DOC: add internals section (GH4082)