*Add into_* methods to StoredValue.*

Currently there is a set of as_* methods on the StoredValue type, which allows for a reference-cast into a specific type. These should be complemented with into_* methods, which take self instead of &self, as there are some places in the codebase where as_foo().cloned() is used when a into_foo() would be better.
This issue is about adding all the missing methods (likely one for each as_* method), as well as examining all callsites in at least the node code and checking whether an into_method fits better.

for background, see this link: https://casper-labs-team.slack.com/archives/C02BSLUGUGM/p1679829582676949