Revamp the example plugin

[dominiklohmann]

• Fixes https://github.com/tenzir/issues/issues/2324

Copilot reviewed 3 out of 14 changed files in this pull request and generated no comments.

Files not reviewed (11)

• CMakeLists.txt: Language not supported
• Dockerfile: Language not supported
• builtins/operators/read_custom_log.cpp: Language not supported
• integration/data/reference/tests/test_parse_example_logs/step_00.ref: Language not supported
• integration/data/reference/tests/test_trim_strings/step_00.ref: Language not supported
• integration/data/reference/tests/test_trim_strings/step_01.ref: Language not supported
• integration/data/reference/tests/test_trim_strings/step_02.ref: Language not supported
• integration/data/reference/tests/test_trimming_non-2dstring_fields_fails/step_00.ref: Language not supported
• integration/tests/setup_suite.bash: Language not supported
• integration/tests/tests.bats: Language not supported
• src/plugin.cpp: Language not supported

Comments suppressed due to low confidence (1)

README.md:3

• The word 'operaotr' is misspelled. It should be 'operator'.

This is an example plugin for Tenzir, adding a `trim` operaotr that removes

[mavam]

I haven't tested the compile cycle, but the annotated source code reads excellent!