Add function or method for deep linking

[evgfilim1]

Is your feature request related to a problem? Please describe.
Would be nice to have a function or method for deep linking as we already have CommandStart filter that can catch such commands easily.

Describe the solution you'd like
Something like

await bot.deeplink('aiogram')

will return 'https://t.me/bot?start=aiogram'

Name of the method and its location is a subject of discussion.

Describe alternatives you've considered
For now I have to write my own function like this:

async def deeplink(arg):
    return f'https://t.me/{(await Bot.get_current().me).username}?start={arg}'