Pipeline component documentation examples reference non existing assets

[ptitzler]

Describe the issue
A clear and concise description of what the issue is.

Some of the CLI examples in https://elyra.readthedocs.io/en/stable/user_guide/pipeline-components.html reference URLs that are no longer valid, e.g. https://raw.githubusercontent.com/elyra-ai/elyra/master/etc/config/components/kfp/filter_text_using_shell_and_grep.yaml. The referenced files were removed when Elyra introduced the examples connectors. The documentation topic needs to be updated to reflect the new URL:

• https://raw.githubusercontent.com/elyra-ai/elyra/master/etc/config/components/kfp/filter_text_using_shell_and_grep.yaml -> https://raw.githubusercontent.com/elyra-ai/examples/master/component-catalog-connectors/kfp-example-components-connector/kfp_examples_connector/resources/filter_text_using_shell_and_grep.yaml
• https://raw.githubusercontent.com/elyra-ai/elyra/master/etc/config/components/kfp/run_notebook_using_papermill.yaml -> https://raw.githubusercontent.com/elyra-ai/examples/master/component-catalog-connectors/kfp-example-components-connector/kfp_examples_connector/resources/run_notebook_using_papermill.yaml