chore: drop Hunter Package Manager

[sleepdefic1t]

Proposed changes

This PR drops Hunter Package Manager in favor of git submodules.

Specifically, this PR does the following:

• drops Hunter & Hunter files.
• adds cURL as a git submodule.
• updates CMakeLists.txt files to find cURL dep.
• updates relevant documentation.
• updates codecov ignore path.
• adds openssl to CI dep install
• updates the changelog.

This also resolves #45

Types of changes

• Build (changes that affect the build system)

Checklist

• I have read the CONTRIBUTING documentation
• Lint and unit tests pass locally with my changes
• I have added necessary documentation (if appropriate)

[codecov-io]

Codecov Report

Merging #90 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master     #90   +/-   ##
======================================
  Coverage    96.4%   96.4%           
======================================
  Files          14      14           
  Lines         250     250           
======================================
  Hits          241     241           
  Misses          9       9

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