Prevent clickjacking with X-Frame-Options header

[palourde]

Description

Prevent Clickjacking by adding the X-Frame-Options response header to all static content.

Related Issue

Motivation and Context

https://www.owasp.org/index.php/Clickjacking_Defense_Cheat_Sheet

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codecov-io]

Codecov Report

Merging #680 into master will decrease coverage by 0.04%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master     #680      +/-   ##
==========================================
- Coverage   21.54%   21.49%   -0.05%     
==========================================
  Files          27       27              
  Lines        2270     2275       +5     
==========================================
  Hits          489      489              
- Misses       1722     1727       +5     
  Partials       59       59

Impacted Files	Coverage Δ
uchiwa/server.go	0% <0%> (ø)	⬆️

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