AC-607: Replace Apache HTTP API Client library

[deepak140596]

Description of what I changed

Removed deprecated Apache HTTP API Client library from build.gradle (app level).

Issue I worked on

JIRA Issue: https://issues.openmrs.org/browse/AC-607

Checklist: I completed these to help reviewers :)

• My pull request only contains ONE single commit
  (the number above, next to the 'Commits' tab is 1).

• I have added tests to cover my changes. (If you refactored
  existing code that was well tested you do not have to add tests)

• All new and existing tests passed.

• My pull request is based on the latest changes of the master branch.

[codecov-io]

Codecov Report

Merging #592 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #592   +/-   ##
=======================================
  Coverage   14.16%   14.16%           
=======================================
  Files         184      184           
  Lines        8557     8557           
  Branches      750      750           
=======================================
  Hits         1212     1212           
  Misses       7270     7270           
  Partials       75       75

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[f4ww4z]

Looks good @deepak140596 , will merge after 2.7.2 is released. Our priority currently is AC-613, can you take a look into it if you have time?