Add support for case, whitespace & separator normalization

[petri]

I understand this may fall outside the scope, but it would be very convenient if cleanco also had this kind of simple normalization built-in:

• standardizing lettercase (e.g., all lowercase)
• standardizing separators (e.g., commas must be followed by spaces)
• standardizing whitespace (e.g., converting all runs of whitespace to single spaces)

[psolin]

• standardizing lettercase (e.g., all lowercase) I disagree. Some companies have odd capitalization, so it is probably best to leave this as-is. Anyone can choose to use the .lower() function later if they want to.
• standardizing separators (e.g., commas must be followed by spaces) This might be a good idea, but I want to think about it (why add something if it breaks other things in the future)

• standardizing whitespace (e.g., converting all runs of whitespace to single spaces) The code already does this:

  business_name = " ".join(business_name.split())

[petri]

To clarify, I meant these to be optional convenience features rather than changing existing behavior - and yes, I did not realize the extra whitespace removal was already there, that's nice.

[petri]

Thinking a bit more about this, the only remaining part of the request (separator normalization) is not really that important, and having lowercase name is trivial so I feel we can close this.