Create a beautiful page for error 404, etc...

[redDwarf03]

Is your feature request related to a problem?

if you go to https://archethic.net/ssss, the page is blank with the error

Describe the solution you'd like

Create a page with the archethic's branding to catch http error

Additional context

No response

[manujuniris]

• [x] Design a beautiful page
• [ ] Make changes inside server to display error.html for errors 404, etc

[redDwarf03]

Concerning the PR https://github.com/archethic-foundation/archethic-website/pull/108, the design is simple but sufficient. But, the code is too heavy. it is not necessary to embed the Terms of Use and all js references for example. please clean the html code