pure codeview-Add files and change class names

[zhilong-xu]

What this PR does / why we need it:

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Special notes for your reviewer:

Release note:

[codecov]

Codecov Report

Merging #299 (19a7a81) into pure (2c761fc) will increase coverage by 0.11%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             pure     #299      +/-   ##
==========================================
+ Coverage   70.54%   70.65%   +0.11%     
==========================================
  Files         163      166       +3     
  Lines       15798    16120     +322     
  Branches     1946     1985      +39     
==========================================
+ Hits        11144    11390     +246     
- Misses       3994     4055      +61     
- Partials      660      675      +15     

Impacted Files	Coverage Δ
delfin/drivers/pure/pure/pure_storage.py	89.06% <ø> (ø)
delfin/drivers/pure/pure/rest_handler.py	50.86% <0.00%> (ø)
delfin/drivers/pure/pure/consts.py	100.00% <0.00%> (ø)
delfin/drivers/fake_storage/__init__.py	95.61% <0.00%> (+0.54%)	⬆️