Allow Hashdiff to be case sensitive seperately from hash keys

[barrystr]

Is your feature request related to a problem? Please describe.
We have a requirement to make hashdiff results case sensitive while keeping the hash keys as case insensitive

Describe the solution you'd like
A clear and concise description of what you want to happen.

Describe alternatives you've considered
I have added a new variable hashdiff_content_casing that can be set to upper or disabled in the same way as the hash_content_casing. Changes were required to standard_column_wrapper to accept the is-hashdiff parameter. hash amd null_expression were changed to pass the parameter.

Additional context
We considered making both the keys and hashdiff case sensitive but we did still need the keys to remain as they were.

AB#5614

[barrystr]

I've applied the changes I made to this codespace - https://expert-space-meme-9g9wxvrwwgp2x9g4.github.dev/