Avoid use of BasicEntityIdParser

Remove use of BasicEntityIdParser which already
has limited knowledge of the types of EntityId objects
(only Item and Property).

The LegacyIdInterpreter still has that limitation,
but can do the equivalent work without needing to
construct a new BasicEntityIdParser object all the time.

The ItemId::newFromNumber and PropertyId::newFromNumber
methods are also not great and would be better if we can
somehow avoid the entity type + numeric id format in
EntityIdValue.
Merge pull request #247 from wmde/idparser

Avoid use of BasicEntityIdParser