Control labels position when plotting Networkx

#### Is your feature request related to a problem? Please describe.
When plotting a graph (given as a Networkx object), there's no easy control on the position of the labels.

```python
G = nx.DiGraph()
G.add_node("a")
G.add_node("b")
G.add_edge("a", "b")
pos = nx.layout.planar_layout(G)
nodes = hvnx.draw_networkx_nodes(
G, pos, with_labels=True
)
edges = hvnx.draw_networkx_edges(
G, pos, arrowstyle="->"
)
nodes * edges
```

Based on the suggestion by @philippjfr [see here](https://discourse.holoviz.org/t/labels-position-when-plotting-netwrokx/1211/4), adding `.opts('Labels', xoffset=.0, yoffset=.09)` to the nodes drawing controls the position of the labels.

This is working as expected but probably could be part of the drawing function itself.