Entity web resource

[jhou-pro]

The lifecycle for entities on entity masters (and other views) includes several actions which should be implemented both at Web UI level and server side level. These entity actions include:

1. Retrieve / refresh
2. Validate (Entity validation web resource #106)
3. Save (modified or new)
4. Delete

The items 1, 3 and 4 at the server side should be implemented as the Entity Web Resource and the item 2 -- as the Entity Validation Web Resource. Web UI component tg-entity-master should incorporate items 1, 3 and 4 at the client level and it should incorporate tg-entity-validator (with item 2) as its inner implementation detail (see #106).

It is crucial to perform smart validation as part of the saving process. Please note that validation is not needed in case when it was already done previously (as part of validation after the editor commit action) and there should be no UI blocking for the user.

It is worthwhile to mention that custom Entity Producer and custom Entity Fetch Strategy should be used for all entity related resources (#106, #115, #119) as it was discussed. It ensures consistency and reuse of that concepts across all entity resources.

[01es]

The following HTTP methods should be supported:

• GET -- request to obtain a existing entity by ID (Entity Fetch Strategy should be used here); in case of missing ID, the request should return a new entity (created using Entity Producer).
• PUT -- request to save a new entity.
• POST -- request to update an existing entity.
• DELETE -- a request to delete an existing entity.

[jhou-pro]

This issue is considered to be implemented as part of Issue-#106 branch and has been merged into develop branch.

All necessary functionality has been implemented including tg-entity-master client side counter-part for master lifecycle.

Note (TODO): please make save action Web UI tests workable without repopulating db every time.