Change case of Bitbucket block names

[discdiver]

First check

• [X] I added a descriptive title to this issue.
• [X] I used the GitHub search to find a similar request and didn't find it.
• [X] I searched the Prefect documentation for this feature.

Prefect Version

2.x

Describe the current behavior

BitBucketCredentials and BitBucketRepository are the two blocks in the prefect-bitbucket library.

Bitbucket is the name of the service, with a lowercase second "b".

Describe the proposed behavior

I propose that BitbucketCredentials and BitbucketRepository become the two blocks in the prefect-bitbucket library. This would be the expected capitalization based on Python CamelCase class conventions.

Example Use

No response

Additional context

This is pedantic, but seems best to have the name match the expected name.