Add plugin deprecation info into registry index file

[mmorhun]

Signed-off-by: Mykola Morhun [email protected]

What does this PR do?

Adds deprecate section of plugin meta information into index.json file of the plugin registry.

If a plagin is not deprecated then nothing will be changed in current model.
If a plugin is deprecated then to its metadata in the registry index.json file will be added deprecate section, which is copy of deprecate section of the plugin meta.yaml file.
For example:

...
deprecate {
    "automigrate":  true,
    "migrateTo": "another_publisher/another_plugin_id:1.0.0"
},
...

This change is needed for dashboard to be able to display deprecation on a plugin and suggest auto migration. See eclipse-che/che#13021

[sleshchenko]

It would be useful to see examples of script work in both cases - for non-deprecated and for deprecated plugins.

[sleshchenko]

Also please consider changing index.json items model in README.md https://github.com/eclipse/che-plugin-registry#get-index-list-of-all-plugins

[mmorhun]

@sleshchenko I had described it in the description, but yes, an example would be even better.
Updated description.

[mmorhun]

As about readme, we have already described the deprecate section. It is just copied to index.json for such plugind, so no need in update.

[sleshchenko]

As about readme, we have already described the deprecate section. It is just copied to index.json for such plugind, so no need in update.

So, but README.md does not give any clue that deprecate is copied to index.json.
I still think that it would be better to paste example of deprecate section to index.json example.

[mmorhun]

@sleshchenko updated