#feature url with IOUtoken address -> page with IOUtoken view

[stanta]

As a buyer of the IOU token, I want to when I open a URL like iou.bz/buy/0x1234567abcdef.... the page to purchase the token 0x1234567abcdef will be show

Also, add feature "share my IOU"|:
add a "share" button in Edit IOU tokens, which would generate and show such a link.

[stanta]

Also, add chain ID to URL like
http://localhost:3000/buy-iou/0x13881/0x0cE4b33dB58De335A141937BC91087Df03B78369

where 0x13881 is the blockchain ID. If this ID is different from the current one, then the chain switching procedure is called, (at src/api/chain.js:67)