Add -Dspringdoc.writer-with-default-pretty-printer as maven plugin configuration parameter

[ilyavy]

Use case: We generate open-api documentation as part of the development process, and then commit the documentation to the repository. Developers use mvn verify, but sometimes they forget about this cumbersome system parameter, and commit one-line generated open-api document to git. It would be much more convenient and practical to have this parameter as maven plugin configuration parameter.

[bnasslahsen]

use [springdoc properties](https://springdoc.org/#properties) directly.