Add support for Saved Searches on REST API

It should be possible to persist a page provider state from REST API, probably with additional segments on the "query" endpoint. Specifications of the endpoint to do. We want to be able to:

• get saved instances for a given page provider name
• create a new saved search instance for a given page provider name and its parameters
• update a saved search
• delete a saved search

In new web ui , sharing a saved search is made without new api, using the document id that holds the saved search information, and the default document-permissions element.

New Search endpoint

Allow to:

• Execute an arbitrary query (returning documents or result sets)
• Execute page provider
• Manage saved searches

Returns any object (that can be marshalled), not only Documents

Execute an arbitrary query

GET /search/lang/{queryLanguage}/execute?query=...
GET /search/lang/nxql/execute?query=SELECT * FROM Document

Execute a page provider

GET /search/pp/{pageProviderName}/execute
GET /search/pp/DOCUMENT_CONTENT/execute

Page provider definition? (if needed)

GET /search/pp/{pageProviderName}

Manage saved search
Create a “SavedSearch” object, with reader and writer, to easily manage them.
A SavedSearch should at least contains:

• An ID if any
• A title
• The page provider name / query (in different fields)
• Categories (flags?)
• The search parameters

Save a search - post a SavedSearch JSON object (including provider name or query, search title, categories (flags), search params

POST    /search/saved

Returns the SavedSearches accessible by the current user, possibly filtered with the query params

GET    /search/saved[?flags=foo,bar&pageProviderName=DOCUMENT_CONTENT]
or
GET    /search/saved[?flag=foo&flag=bar&pageProviderName=DOCUMENT_CONTENT]

Get a saved search - get a SavedSearch JSON object

GET     /search/saved/{id}

Update a saved search

PUT     /search/saved/{id}

Delete a saved search

DELETE  /search/saved/{id}

Execute a saved search, return the result, accepts pagination parameters

GET     /search/saved/{id}/execute

TODO: discuss migration or compatibility use cases between existing saved searches, based on content views, and new ones created by REST (and are they visible in the JSF UI?)