Improving whole site by fixing some issues

[ben221199]

This pull request fixes some problems, like:

• Disappearing pages (see #77)
• Disappearing projects using Multiformats
• Removing outdated dependencies, eventually replacing them with alternatives.
• Improving some title properties.
• Improving sitemap.xml
• Adding robots.txt and adding sitemap to it.

[rvagg]

this is really nice, thanks @ben221199; just a couple of items I've commented on inline

[ben221199]

Thanks for reviewing @rvagg. I will give a look at them.

[ben221199]

I improved the code. The logo now works.

[ben221199]

Yeah, that base_url was some quick fix to solve it.