Sets the collection's default time-to-live value.
The default time-to-live value on a collection is an optional property. If set, the documents within the collection
expires after the specified number of seconds since their last write time. The value of this property should be one of the following:
null - indicates evaluation of time-to-live is disabled and documents within the collection will never expire, regardless whether
individual documents have their time-to-live set.
nonzero positive integer - indicates the default time-to-live value for all documents within the collection. This value can be overridden
by individual documents' time-to-live value.
-1 - indicates by default all documents within the collection never expire. This value can be overridden by individual documents'
time-to-live value.