Doumentation missing: ocm install command and plugins in general

[jensh007]

What happened:
The cli-reference at https://ocm.software is missing the command ocm install

The documentation on ocm-software should get a section about plugins in general:

• What is the purpose of plugins?
• What kind of plugins exist and what extensions points exist (e.g. upload/download handler)?
• How are they installed and configured?
• Configuration example for the demo plugin
• Running the demo plugin
• Credential handling

What you expected to happen:
Added documentation

How to reproduce it (as minimally and precisely as possible):
n/a

Anything else we need to know:

Environment:
n/a

[ikhandamirov]

Regarding installation: https://github.com/open-component-model/ocm/blob/main/docs/reference/ocm_install_plugins.md

[morri-son]

Regarding installation: https://github.com/open-component-model/ocm/blob/main/docs/reference/ocm_install_plugins.md

@ikhandamirov @Skarlso (as I know you heavily worked on getting the cli reference synced to the website): Can you please check why the install command has not been synced to the webpage?