Replace WSK reference with Adobe I/O CLI Instructions

[sarahxxu]

To do:

• Replace reference to Openwhisk CLI and wskdeploy CLi with reference to AIO CLI
• Add links to AIO CLI

Pages to update:

• https://github.com/AdobeDocs/adobeio-runtime/blob/master/README.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/quickstart.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/overview/howitworks.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/getting_started.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/getting-started/setup.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/getting-started/deploy.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/getting-started/activations.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/guides.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/guides/creating_actions.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/guides/asynchronous_calls.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/guides/throughput_tuning.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/guides/securing_web_actions.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/guides/creating_rest_apis.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/guides/using_packages.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/guides/logging_monitoring.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/guides/debugging.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/guides/system_settings.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/guides/ci-cd_pipeline.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/reference.md
• Add description and more usage samples https://github.com/AdobeDocs/adobeio-runtime/blob/master/reference/cli_use.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/reference/prepackages.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/reference/runtimes.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/reference/triggersrules.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/reference/sequences_compositions.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/reference/packages.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/reference/feeds.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/tools.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/tools/cli_install.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/tools/wsk_install.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/tools/wskdeploy_install.md
• https://github.com/AdobeDocs/adobeio-runtime/blob/master/reference/wsk_use.md

[sarahxxu]

• Add a summary description on the overall tooling level, what is the history with wsk cli, why should a user switch to use AIO CLI instead
• Add a summary on how configuration and secret reading should work (the fallback rules with aio cli, what's the priority of config reading)
  • confirmation that .wskprops will still work as the fallback