Add support for assigning literal value to sequence property

Add support for assigning literal value to sequence property

It is a language semantic that we allow clients to assign a single
value to a sequence/list property (assuming that the types match).
Now that we support sequence types, this commit adds support for
this semantic by determining whether the built-in type of the literal
corresponds to the associated sequence (eg, int for QList<int>, qreal
for QList<qreal>, bool for QList<bool>, QString for QStringList etc).

Similarly, some value types can be constructed from literal string
values (via string converters) and these need to be handled also.

Task-number: QTBUG-18062
Task-number: QTBUG-21770
Change-Id: Iacd91b2af122cd8f20b7df2fa6056a7d7c52bf53
Reviewed-by: Aaron Kennedy <aaron.kennedy@nokia.com>