Add 'share' control with prefilled business name or address

[CloCkWeRX]

Scenario: I'm talking about openstreetmap with someone who owns a business; but I don't know 100% of their details.
It should be easy for me to invite them to contribute to OSM.

Steps I'd expect to be able to take:

1. I can fill in some detail like address or name
2. I'm given a shareable link with a single click (copy to clipboard, or a mailto link with ?subject/?body params filled
3. On clicking the link, some data is prefilled - ie: https://onosm.org/?name=Joe%27s%20Shoe%20Emporium&address=123%20Example%20Street%20Exampletown would set the address and name fields, triggering the search.

[CloCkWeRX]

First pass at it using a cheap and cheery button generator in https://github.com/CloCkWeRX/onosm.org/tree/share_controls :

Have to do more to make the i18n bits work though