Added custom YLabel and Custom content on tooltip

[sbengo]

Actually, custom label are not allowed, it directly uses the provided by
the query result as the target/alias

This feature allows to:

• Split YLabel to store its partials and reuse them on link and extra tooltip field
• Override YLabel with splitted and custom values
• Added Custom Content to show metadata to the user on each serie

This PR fixes #152

Thanks,
Regards

[diafour]

Looks good. There are minor naming issues, but I'll fix them in a separate PR that will rework customContent into a new item type.

Will you add more PRs in the near future? There is a huge update coming to migrate the plugin to grafana-toolkit.

[sbengo]

Thanks for the comment @diafour !

I like the rework of the customContent in new type item, but as I told you I suppose that it will break with the actual item definition, used for links

This PR #153 and #148 fills our needs to complete our current project (the real case described on issue), so I have no plans to do more PRs related with.
I suppose that the incoming migration to grafana-toolkit will break (short term), with Grafana 6.X, and as I told you in the related PR issue, we cannot manage a Grafana 7.X migration right now...

So, with the above I would ask you:

• Can this PR be merged, so we can use the upstream plugin (not a release, but pointer to commit)?

Thanks again for your feedback,
Regards!

[diafour]

I suppose that it will break with the actual item definition, used for links

Don't worry, it should not break existing panel configurations. There is a config migration for this purpose.

I suppose that the incoming migration to grafana-toolkit will break (short term), with Grafana 6.X

I thought it that way, but surprisingly the plugin works great in 6.6.2 after building by @grafana/toolkit 7.3.4. I plan to test more versions of Grafana and I think 6.2 or 6.3 will be the minimum supported version after the update.

Can this PR be merged

Yes! Thank you for your time and efforts! I merge it now.