Disallow glob paths with `**` that is not a folder segment

[jaychia]

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

Daft currently only correctly understands the ** recursive wildcard when it is applied to a folder segment. I.e.

• s3://bucket/**.csv is not valid
• s3://bucket/**/*.csv is valid and conveys the intended behavior

We should provide an appropriate error message when we detect the former, or perhaps sanitize the input when we find instances of ** not enclosed by /.

[nemo-1999]

I would like to work on this

[nemo-1999]

take

[conradsoon]

hey @jaychia, i'd like to give this a shot :)