Adding the possibility for CORS requests to the pursuit API

I'm building a webapp where I'd like to add pursuit search, but fetch requests to pursuit are failing due to access control issues.

I think this could be solved by adding ie:

optionsSearchR :: Handler RepPlain
optionsSearchR = do
    addHeader "Access-Control-Allow-Origin" "*"
    addHeader "Access-Control-Allow-Methods" "GET, OPTIONS"
    return $ RepPlain $ toContent ("" :: Text)

getSearchR :: Handler TypedContent
getSearchR = do
    addHeader "Access-Control-Allow-Origin" "*"

Are there any objections to this? If not I'll make a PR.

Locate the pursuit API handlers for the search endpoint, especially optionsSearchR and getSearchR mentioned in the issue. Check how request methods and response headers are handled there, then verify that browser search requests and their OPTIONS preflight receive the requested CORS headers.