feat(idempotent): Include function name in the idempotent key

[michaelbrewer]

Issue #, if available:
#318

Description of changes:

Prefix the hashed_idempotency_key with the context function name:

f"{context.function_name}#{self._generate_hash(data)}"

NOTE: Rather than hash this prefix, I kept it in the clear to make debugging a little easier and I did not make
this configurable, as this makes sense as the default

HOWEVER: You MIGHT get edge cases where the function name has been changed while keeping an existing datastore

Checklist

• Meet tenets criteria
• Update tests
• Update docs
• PR title follows conventional commit semantics

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[michaelbrewer]

@heitorlessa what do you think of this ?

[heitorlessa]

Great, thanks!!! Only change here is that we shouldn't add this extra parameter to include function_name, but make it the default.

Because we're in Beta this won't cause any distress, and due to the fact changing a Function name is not possible from an API perspective - IaC triggers a replacement instead.

[heitorlessa]

Thanks a lot for the changes @michaelbrewer, as always ;)

Added a note to update docs to emphasize you can now use a single DDB table to store idempotence state if you wish