Use a text box with number format to enter quantity in config flow

[uvjim]

Checklist

• I have filled out the template to the best of my ability.
• This only contains 1 feature request (if you have multiple feature requests, open one feature request for each feature request).
• This issue is not a duplicate feature request of previous feature requests.

Is your feature request related to a problem? Please describe.

The config flow contains a label to "optionally" enter the number of batteries a device takes. It's possible to enter this in a format that doesn't like up with that used by the sensor when completed via the library. This creates an inconsistent view in the UI.

Describe the solution you'd like

A textbox in the config flow to allow entry of the quantity (defaulting to 1). This would allow processing and for atting the same way as those populated by the library.

Describe alternatives you've considered

Defining the format of entry in the label stating that it is optional.

Additional context

The entry screen in the config flow.

Badly formatted battery type with quantity.

Correctly formatted battery type from library.

[andrew-codechimp]

I like the quantity input idea but as I'm in the code today I've quickly adding a hint until I can work on it more.

[andrew-codechimp]

I have a migration plan to fully achieve this which I'll be rolling out in the next few weeks, see #421