Add chainable query builder interfaces

[tchak]

Adds chainable query builders. This is a huge DX improvement in my opinion.

Query:

store.findRecords('planet')
  .sort('classification', '-name'))
  .filter({ attribute: 'classification', value: 'terrestrial' });

Peek:

store.findRecords('planet')
  .sort('classification', '-name'))
  .filter({ attribute: 'classification', value: 'terrestrial' })
  .peek();

Live Query:

store.findRecords('planet')
  .sort('classification', '-name'))
  .filter({ attribute: 'classification', value: 'terrestrial' })
  .live();

Live Peek:

store.findRecords('planet')
  .sort('classification', '-name'))
  .filter({ attribute: 'classification', value: 'terrestrial' })
  .live()
  .peek();

[tchak]

I am planing on adding another round of deprecations with this. But everything is backward compatible.

It is also interesting to see this in conjunction with #240. It will be possible to write :

store.findRecord({ type: 'planet', id: '1' })
  .peek().hasMany('moons')
    .query()
    .sort('name')
    .live()
    .peek();

store.findRecord({ type: 'planet', id: '1' })
  .peek().hasMany('moons')
    .query()
    .page({ offset: 0, limit: 10 }));

[tchak]

This PR also alignes findRecord with EmberData to take a RecordIdentifier

[tchak]

I added live interface only to findRecords and findRelatedRecords to mitigate #178. We can revisit this later when we have a better solution for LiveQuery.

[tchak]

superseded by #278