Improve Performance of Validator

Our goal is to improve the performance of `SchemaValidatorImpl.java`.

We found already some starting points to improve the performance like:
* reduce the excessive usage of regular expressions

We also saw that the current implementation makes it hard to investigate performance issues and want to improve the following:
* split the large `validate` method in `SchemaValidatorImpl.java` by extracting the single if statements into separate methods.

To be able to measure our performance improvements we want to create small jmh benchmarks in `vertx-json-schema` with the following characteristics:
* test the same value during one benchmark