processor: new enhancements, API changes and new processor

[edsiper]

Log processing example:

pipeline:
  inputs:
    - name: dummy
      dummy: '{"key1": "123.4", "key2": "true", "key3": "delete me", "message": null, "http.url": "https://www.google.com/search?q=example"}'
      rate: 1

      processors:
        logs:
          - name: content_modifier
            action: insert
            key: "new_key"
            value: "new_value"

          - name: content_modifier
            action: upsert
            key: "message"
            value: "this kv should be at the end"

          - name: content_modifier
            action: delete
            key: "message"

          - name: content_modifier
            action: rename
            key: "new_key"
            value: "new_key_renamed"

          - name: content_modifier
            action: hash
            key: "message"

          - name: content_modifier
            action: extract
            key: "http.url"
            pattern: ^(?<http_protocol>https?):\/\/(?<http_domain>[^\/\?]+)(?<http_path>\/[^?]*)?(?:\?(?<http_query_params>.*))?

          - name: content_modifier
            action: convert
            key: "key2"
            converted_type: boolean

  outputs:
    - name : stdout
      match: '*'

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Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.