Added new functionality for organizational network analysis (ONA):
- Introduced `p2p_data` and `g2g_data` sample datasets, with an option to simulate a person-to-person dataset using `p2p_data_sim()`
- Added `network_g2g()`, `network_p2p()`, `network_summary()`, and `create_sankey()` functions
- `network_p2p()` now has a `centrality` argument for computing and visualizing centrality as node sizes in the network plot
- For `network_p2p()`:
- the `algorithm` argument is renamed to `layout` for better intuitiveness
- Improved consistency and intuitiveness of the API, with `style` argument now controlling the network plotting mechanism and `return` argument controlling whether plots are generated interactively or saved as PDF
- Added a large number of community detection algorithms from `igraph`