Config export modal

[VakarisZ]

What does this PR do?

Creates a modal window/popup for configuration export.

Mockup:

Results:

PR Checklist

• Have you added an explanation of what your changes do and why you'd like to include them?
• Is the TravisCI build passing?
• Was the CHANGELOG.md updated to reflect the changes?
• Was the documentation framework updated to reflect the changes?

Testing Checklist

• Added relevant unit tests?
• Have you successfully tested your changes locally? Elaborate:

  Tested manually, by using all of the functionality in the popup: close modal, enter password, switch to plaintext, switch back to password, etc.

• If applicable, add screenshots or log transcripts of the feature working

[codecov]

Codecov Report

Merging #1189 (a0487f4) into develop (243642c) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #1189   +/-   ##
========================================
  Coverage    28.83%   28.83%           
========================================
  Files          424      424           
  Lines        12893    12893           
========================================
  Hits          3718     3718           
  Misses        9175     9175           

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