Edit 404 page

[akeamc]

• New text (that is VERY informative)
• Link that takes the user back to the main screen
• Same styles as before

[aerori]

Please see issue #120 for some more requirements. Mainly this:

Suggest a set of probable wanted pages via Levenshtein.

[veksen]

Hiya! I appreciate the PR, but I would like to see at least one of the 3 main things from the issue:

• update to styling
• update to add a list of possible pages that are matching
• add specific handling for resources vs main pages

[veksen]

Closing as per discussed. If you wish to make a contribution, feel free to come back with at least one of those 3:

• update to styling
• update to add a list of possible pages that are matching
• add specific handling for resources vs main pages