[RFR] Introduce new way to define dashboard datasources

[fzaninotto]

Depends on marmelab/admin-config#14

// customize dashboard
admin.dashboard(nga.dashboard()
    .addCollection('posts', nga.collection(post)
        .title('Recent posts')
        .perPage(5) // limit the panel to the 5 latest posts
        .fields([
            nga.field('title').isDetailLink(true).map(truncate)
        ])
        .order(1)
    )
    .addCollection('comments', nga.collection(comment)
        .title('Last comments')
        .perPage(5)
        .fields([
            nga.field('id'),
            nga.field('body', 'wysiwyg')
                .label('Comment')
                .stripTags(true)
                .map(truncate),
            nga.field(null, 'template') // template fields don't need a name in dashboard view
                .label('')
                .template('<post-link entry="entry"></post-link>') // you can use custom directives, too
        ])
        .order(2)
    )
    .addCollection('tags', nga.collection(tag)
        .title('Recent tags')
        .perPage(10)
        .fields([
            nga.field('id'),
            nga.field('name'),
            nga.field('published', 'boolean').label('Is published ?')
        ])
        .order(3)
    )
);

• add support for new nga.dashboard() syntax
• Add compatibility layer to make old dashboardView() work
• clean up dashboard view
• rename PanelBuilder
• document new syntax
• Add example of custom dashboard
• Fix tests

[jpetitcolas]

I would also add a few words about Restangular element transformers.

[fzaninotto]

I refer to the extensive documentation chapter about API Mapping two lines down, I think it's enough.

[jpetitcolas]

Fine for me, even if there may be a confusion between the collection name, which is sometimes used as a listView in the ReadQueries.getAll method for instance. We should consider (probably in another PR) to homogenize these names.

[fzaninotto]

I'm also not very happy about the addition of a new concept, but this one goes in the right direction (separating data from presentation). listView mixes three concepts: the definition of the collection to fetch (fields, per page, etc.), the presentation (title, filters, etc), and the features (filters, actions). As it's all-or-nothing, I preferred to introduce this collection concept, which is what should be used in every ReadQuery instead of view. But that's, as you said, for another refactoring.

[fzaninotto]

Green!

[fzaninotto]

Back to WIP, I discovered a regression in dashboard panels title

[fzaninotto]

And we're back to RFR.