Add a `get_all` method to `RootEntity` to get the all the stored data

[andrea-mucci]

Is your feature request related to a problem? Please describe.
If we need to ask for all the RootEntities that are stored, wich kind of method we use? at the moment the two queriies method are get and find but the get_all() method, for example is not present

Describe the solution you'd like
add a method get_all() that return the entire RootEntities set

Describe alternatives you've considered
at the momento have no alternatives

[garciparedes]

Hi @andrea-mucci!

Currently, we have a way to do that through the find method and Condition.TRUE, which is satisfied by all the root entities stored on the database.

But I agree with you, adding a get_all method will provide the same functionality in a more intuitive way.