Bugfix: make Louvain implementation in network_p2p() deterministic (#221)

[martinctc]

Summary

This branch fixes a bug reported in #221 where the Louvain implementation in network_p2p() cannot be made deterministic.

Changes

The changes made in this PR are:

1. Expands the ability to set seed within the function environment with the seed argument in network_p2p() to when display = "louvain" (previously only affects display = "leiden").
2. Update relevant documentation.

Validation

This fix is confirmed to be working with:

library(wpa)

p2p_data <- p2p_data_sim()

a <- 
  p2p_data %>%
  network_p2p(
    display = "louvain",
    return = "table",
    seed = 100
  )

b <- 
  p2p_data %>%
  network_p2p(
    display = "louvain",
    return = "table",
    seed = 100
  )

nrow(a) == nrow(b)

all(a$cluster == b$cluster)

Checks

• All R CMD checks pass
• roxygen2::roxygenise() has been run prior to merging to ensure that .Rd and NAMESPACE files are up to date.
• NEWS.md has been updated.

Notes

This fixes #221.