Add meta_util.schema procedure that generates graph schema as a graph result

[tonilastre]

Description

Module meta_util can be used to generate a graph schema as a graph result. It can be used like this:

// Get schema without properties count
CALL meta_util.schema() YIELD nodes, relationships RETURN nodes, relationships;

// Get schema, but with properties count
CALL meta_util.schema(true) YIELD nodes, relationships RETURN nodes, relationships;

It will show graph view only in Lab version >= 2.4.0. For earlier versions of the Lab, UNWIND needs to be called on returned object properties nodes and edges.

Pull request type

• Algorithm/Module

Module/Algorithm

• Query module implementation
• Unit tests
• End-to-end tests
• Code documentation
• README short description
• Documentation on memgraph/docs - [master < T1023-DX] Add meta_util module docs docs#646

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[antepusic]

All looks OK, just check out the suggestions I left 😄

[antepusic]

Good job!

[antoniofilipovic]

Looks good, but from the optimization side, I think we should make this change of order when checking if the graph is empty, and make sure tests don't break.