Add syntax highlighting to the backup page

[GentlemanHal]

Some investigation into the best library to use will need to be done.

Possible options:

• https://highlightjs.org/download/
• https://github.com/antonmedv/codejar#getting-started
• https://prismjs.com/

Whatever we pick we should lazy load it to avoid bloating the initial bundle.

[tharun208]

I like to work on this