HTML and Javascript code cleanup

[christian-thieme]

• currently the html and javascript for the passkeys package is separated into multiple files which can be combined into one html and one javascript file for easier integration
• The javascript contains django template tags, is poorly structured, should be done by function parameters instead
• files with .js ending are actually django templates which confuses text editors

[mkalioby]

You can open PR for that

[mkalioby]

Also check #27

[christian-thieme]

see #48