Expose a search query parameter

[danneu]

It would be nice to be able to link to a search.

For example, in IRC the topic of elm-history came up and how the 0.16 version was hosted at a new location.

Being able to link to e.g. /?q=history would've been a nice way to communicate together the status of elm-history and also the new location it can be found at:

Additional polish would entail auto-updating the ?q=... query parameter (without changing the history stack) and also removing the parameter from the url when the user clicks out of search.

[prikhi]

Would love this to be a part of 0.19. Recently got duckduckgo to add a !elm bang that lets you search elm-search: https://duckduckgo.com/?q=%21elm+Maybe+%28Maybe+a%29+-%3E+Maybe+a

Would love to be able to use !elmpkg to search package.elm-lang.org.