Disallow or explicitly allow spec quantity to be specified with a numeric string

[dsleiter]

The codebase seems to assume that a spec quantity is either a string from a reserved set of special characters or named wildcard quantities or an integer value. However, the spec schema documentation does not seem to exclude numeric strings and DatasetSpec accepts a numeric string quantity.

>>> from hdmf.spec import DatasetSpec
>>> ds = DatasetSpec('A Dataset', data_type_inc='Foo', quantity=1)
>>> ds.is_many()
False
>>> ds = DatasetSpec('A Dataset', data_type_inc='Foo', quantity='1')
>>> ds.is_many()
True

I'm not sure if this is a problem that's actually been encountered, but it seems likely to come up at some point.

Is your feature request related to a problem? Please describe. This came up while testing #526 and trying to determine what edge cases needed to be tested.

Describe the solution you'd like Options:

• disallow numeric strings in the schema documentation and in BaseStorageSpec
• explicitly allow it in the documentation and convert numeric strings to integer value in BaseStorageSpec.__init__

Describe alternatives you've considered Treat both integer and numeric strings in all cases where quantity is used.

Additional context None

Checklist

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