Support for dynamic renaming of keys

[divbok]

Description

It includes support for dynamic renaming of keys in rename processor where the user can now give a regex pattern to match the keys that needs to be replaced.

Issues Resolved

Resolves #4849

Check List

• New functionality includes testing.
• New functionality has a documentation issue. Please link to it in this PR.
  • New functionality has javadoc added
• Commits are signed with a real name per the DCO

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[oeyh]

Nice work! A few minor issues in addition to David's comments.
Also, not blocking this PR, have you got a chance to take a look at adding the to_key_pattern option as well? It would be great value added. We can add it in a separate PR if it's straightforward to do.

[divbok]

@oeyh Haven't got a chance yet to look at the to_key_pattern. I can analyse the complexity and see how it goes. Will raise a separate PR if it is trivial.

[oeyh]

Build is failing due to this. Imports need to be explicit.

[oeyh]

This doesn't work when Data Prepper reads config from a yaml file. This constructor is not called. We probably want to move it to getFromKeyCompiledPattern() method.

        public Pattern getFromKeyCompiledPattern() {
            if (fromKeyPattern != null && fromKeyCompiledPattern == null) {
                fromKeyCompiledPattern = Pattern.compile(fromKeyPattern);
            }
            return fromKeyCompiledPattern;
        }

[oeyh]

@dlvenable Are you OK with this approach? This change is for it to work with the example data provided in #4849, where "|" appears in field keys. Without it, the processor fails to delete the original field due to invalid char "|" in the key with a config like this:

    - rename_keys:
        entries:
          - from_key_pattern: "delivered_at.+"
            to_key: "delivered_at"

[oeyh]

Discussed offline. We agree on skipping the validation for the delete method.