Update server examples with scopes and collections

When new sample buckets become available with scopes and collections, update the N1QL examples to make use of them where appropriate.

The travel-sample bucket is being updated so that all existing records will be stored within a scope called inventory. Within that scope, there will be five collections: airport, hotel, landmark, airline, route. Each flavor of record (as distinguished by the type field) is now stored within its own proper collection. (Note that each record will still contain the type field, even though it is hardly needed any more.)

For the beta refresh, N1QL examples need to be updated as follows:

1. All examples must use `travel-sample`.scope.collection rather than `travel-sample` — except for those cases where we are demonstrating query context, in which case the example must use collection.
2. Any queries which filter on type should remove the filter. If necessary, replace with a filter on some other field — see note below.
3. Use judgement to ensure that examples still illustrate the concept that they are intended to.

So, for example:

SELECT * FROM `travel-sample` WHERE type = "airport" AND country = "France";

Would become something like:

SELECT * FROM `travel-sample`.inventory.airport WHERE country = "France";

Note: If you need to demonstrate filtering different "flavors" of document, e.g. to create a partial index, use the activity field in the landmark collection.