Retrieving resources when accessing Resource.<attribute>

Following a discussion on Slack with @pafonta and @MFSY :

Currently, with some of the linked resources, the only way to navigate to a wanted resource (due to how they are registered on Nexus) is the following:

```python
"""
a: instance of kgforge.core.Resource
path: instance of list
forge: instance of kgforge.core.KnowledgeGraphForge
"""

r = a
path = ['b', 'c', 'd', 'e', 'f']
for x in path:
rid = r.get(x).id
r = forge.retrieve(rid)
```

I wanted to open up a discussion for being able to traverse the path in these cases without the user having to call for the for the `forge.retrieve` in each step. I.e. the user would be able to do:

```python
"""
a: instance of kgforge.core.Resource
"""

f = a.b.c.d.e.f
```

Whether or not it is feasible, risky, useful, or if it should or should not be implemented, is up for discussion.