[Enhancement] Useful links after game search

[hydrian]

At the end of a game search, add the two links/functions that should really be there.

"Search Unpublished Games"

Many people think that games installer aren't available or even started because don't know they should also use the 'show unpublished' filter option. Having a link to enable the same search with 'show unpublished' filter enabled, would help in duplicate entries or confusion if a game is supported by Lutris.

"Add The Game"

In the current website, the link to 'add the game' isn't readily findable. You have to search for a game that you know is not going to hit a match result so you get a blank search and then the link to 'add the game' to show up. This link should always be available at end of a game search query.
This is a common question in the #lutris_support and #writting_installer discord channels

[e2298]

I just created a pull request with a fix for this issue. However, I don't know how to link it to this issue.