Improve the examples

**Community Note**
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**Graph Notebook Version (and Graph Database and Version used if applicable)**

Applicable to all versions and all graphs.

**Is your feature request related to a problem? Please describe.**
I believe the default examples that comes with the notebook can be improved.

1. [01-About-the-Neptune-Notebook.ipynb]
1. Put Gremlin or OC as first example.
2. Make examples consistent across languages (The SPARQL example is meaningless). Maybe something like the Gremloin exa mple but expanded with edges too.
2. [03-Using-RDF-and-SPARQL-to-Access-the-Graph.ipynb]
3. The example is meaningless, maybe something like the gremlin example would be better.
4. [04-Social-Network-Recommendations-with-Gremlin.ipynb]
5. The first cell runs a full drop of the database. Maybe a little dangerous.
2. [05-Dining-By-Friends-in-Amazon-Neptune.ipynb]
4. There is no OC/OpenCypher in the name. How users know this is about that?

**Describe the solution you'd like**
Improve the examples to be more user friendly. Imagine sombody with no graph experience is will read them.