Contrast-Finder-Firefox v0.3.3

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* develop: (52 commits)
  set version to 0.3.3
  doc: typo
  typo
  updated URL
  Github templates for Issue and PR: rephrased content
  Added ISSUE_TEMPLATE + PULL_REQUEST_TEMPLATE
  update README : add license badge
  update /docs/Images/
  update .gitignore
  update name + package.json
  update name in docs/en/*.md
  move screenshots in /docs/en/
  add CONTRIBUTING.md
  add CODE_OF_CONDUCT.md
  Initial fork from Tanaguru/Contrast-Finder-Firefox
  move documentation in docs/en/
  Updated Home (markdown)
  Updated Technical documentation (markdown)
  Updated Technical documentation (markdown)
  Updated Technical documentation (markdown)
  ...