Make the following changes to the LiteParsedQuery interface:

Expose LiteParsedQuery(NamespaceString nss) and validate().
Delete makeAsOpQuery() and makeAsFindCmd().
Create setters and getters for all members.

Additionally, remove all overloads of CanonicalQuery::canonicalize() except:
canonicalize(const QueryMessage&, const ExtensionsCallback&),
canonicalize(LiteParsedQuery*, const ExtenstionsCallback&), and
canonicalize(const CanonicalQuery&, MatchExpression* root, const ExtensionsCallback&).
Callers of all other overloads should construct a LiteParsedQuery.