Author content for Intra-device sync

Just simple tweak:

In modules/ROOT/pages/_partials/commons/common-dbreplica.adoc

where it says "between two local databases",

Add that this can be at database, scope, or collection level.

(This will then be expanded on by the code example, requested in separate subtask)

This section from PRD may provide useful wording/explanation:

User must be able to define database-to-database sync at

• Couchbase Lite database level 
• All collections in all scopes in database will be will be synced subject to filter policies.  Implicit mapping rules will be applied

• Couchbase Lite  Scope level 
•  All collections associated with scope will be synced subject to filter policies. Implicit mapping rules will be applied

• Specific collection

Note that the sample code for e.g. C# has been updated and mentions Collection

var targetDatabase = new DatabaseEndpoint(database2);

var config = new ReplicatorConfiguration(targetDatabase)

{

    ReplicatorType = ReplicatorType.Push

};

config.AddCollection(collection);

var replicator = new Replicator(config);

replicator.Start();