Extension mechanism for plugins

[Ole Lensmar]

Plugins should be able to provide:

• navigator sections
• global actions to be added to either the left or right toolbar
• resource-type specific
  • editors / views
  • link-resolvers
  • actions
  • schemas/uiSchemas and specific extensions to the form editor
    ?

[Ole Lensmar]

@devcatalin I think the core of this has been fleshed out - can we close?

[Catalin]

@olensmar we don't have the plugin types specified in the description of this issue, but we could create separate issues for each point. If we close this, the readme file should also be updated because it references this issue