OMERO.matlab: add object creation functions (see #10637)

See https://trac.openmicroscopy.org.uk/ome/ticket/10637
Adds a couple of functions to create basic objects (project, dataset, plate, screen) and upload them onto the server.

Can be tested for projects/datasets with:

```
project = createProject(session, name); %Create a project
dataset = createDataset(session, name); %Create a dataset
dataset = createDataset(session, name, project);  %Create a dataset within project
dataset = createDataset(session, name, projectId);  %Create a dataset within project identified by projectId
```

and for screens/plates with:

```
screen = createScreen(session, name); %Create a screen
plate = createPlate(session, name); %Create a plate
plate = createPlate(session, name, screen);  %Create a plate within a screen
plate = createPlate(session, name, screenId);  %Create a plate within screen identified by screenId
```

NB: when associating a dataset or plate to a project or screen, the object is reloaded using getDatasets or getPlates to prevent unexpected behaviour like in https://www.openmicroscopy.org/community/viewtopic.php?f=6&t=5119 

/cc @yalexand, @imunro, @mporter-gre