Define consistent behaviors for FromSql and ToQuery methods used with complex mappings

[ajcvickers]

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For example, what shape is the query expected to return for entity types mapped in different ways, such as TPT vs TPH.

Done in 8.0

• Support raw SQL queries without defining an entity type for the result #10753

Backlog

• Add hierarchy support for ToQuery #21660
• Enable flexible FromSql mapping #21627
• FromSql() and owned type with table splitting #18616
• Query: FromSql with auto-included navigations sharing same table #21781
• Query: API to check expected shape of FromSql #21826
• API to mark ToQuerySql as non-composable #21827
• Allow non-composable raw SQL queries for TPH non-root types #24157
• FromSql(): Support passing a preamble SQL string #4976
• Query: AsSplitQuery with FromSql Containing output DbParameter #22498
• FromSql: Support multiple resultsets #8127
• Relational: Provide query execution escape hatch APIs that operates a the whole query level #14525
• FromSqlRaw() and ParameterDirection.Output #21433