New plugin "kn-plugin-search" for plugin discovery

[rhuss]

In order to move forward with allowing users to discover available plugins, it is proposed to create a new plugin kn-plugin-search which introduces a kn plugin search command set queries a list of plugins from a fixed URL (e.g. hosted on the knative.dev website). This should be a YAML file, which contains information about:

• Plugin name
• Download location
• Version information
• Short description (1 line)
• Longer Description
• Usage Example
• Maybe: Tags

It should be possible to search with name and within the description. Also, an option should be added (e.g. --all for listing all plugins.

The output should by default fit on one line (like in apt-cache search), but a --verbose should enable the full output (including the full description & usage example). Maybe we could decide to show the full output, too, when only a single search result was detected.

This is the first step towards a more complete solution for dynamic discovery from within e.g. a GitHub organization via a naming convention, borrowing some ideas from brew and krew.

[github-actions]

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[dsimansk]

/remove-lifecycle stale

[github-actions]

This issue is stale because it has been open for 90 days with no
activity. It will automatically close after 30 more days of
inactivity. Reopen the issue with /reopen. Mark the issue as
fresh by adding the comment /remove-lifecycle stale.