tidy_phone: Clean up phone numbers
In tarakc02/preprocessr: Tools to clean up messy strings

Remove any non-numerals from a phone number and shorten it to a fixed length

1	tidy_phone(phone, length = 10, side = "right")

`phone`	character vector of phone numbers
`length`	length to truncate number to (chopping off numerals from the right)
`side`	which side of the string do you want to take? if a lot of phone numbers have country codes which you can remove, then taking the rightmost digits (side = "right") will work