Add initiator filter with alias field

[joseph-v]

What this PR does / why we need it: Add storage host initiator filter with alias field

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #647

Special notes for your reviewer:

Release note:

[codecov[bot]]

Codecov Report

Merging #830 (72b6cd1) into master (cf6bb3b) will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #830   +/-   ##
=======================================
  Coverage   70.58%   70.58%           
=======================================
  Files         180      180           
  Lines       18653    18653           
  Branches     2750     2750           
=======================================
  Hits        13166    13166           
  Misses       4645     4645           
  Partials      842      842           

Impacted Files	Coverage Δ
delfin/api/v1/storage_host_initiators.py	57.14% <ø> (ø)

[sushanthakumar]

LGTM