Pull mod information by web scraping

[hbjydev]

One of the issues I have when trying to configure Reforger servers is that you often need mods' dependencies for the game to be able to install the mod you're trying to add. It'd be real nice if we could scrape the mod page for the mod you're adding (via POST /servers/{id}/mods) to automatically add that mod's dependencies, and even better if we could make some sort of dependency graph so when the user tries to remove a dependent mod, we could tell them that's invalid because mods A, B, and C depend on it, etc as well as auto-cleaning mods when mods were added as dependencies but no longer have any dependent mods.

Example:

Mod A (manual)
Depends on:
  - Mod B
  - Mod C

Mod B (auto)

Mod C (manual)
Depends on:
  - Mod B

1. User removes Mod A
2. Mod B and Mod C remain loaded
3. User removes Mod C
4. Mod B and Mod C both are unloaded

• Mod C was the only mod depending on Mod B and it wasn't manually-added, so we can safely drop it from the config