refactor: Prepare to have more than one event type

[eseidel]

Refactored our PatchInstallEvent to be just PatchEvent
and allow us to have more than one event type.

I moved it into its own events.rs file and added privacy
warnings to both this and the network code (eventually
we may move all this into a separate privacy.rs file).

I also fixed our build.rs file to not panic when our build
is otherwise broken. For whatever reason that seems to
cause the rust-analyzer to stop and not show any future
warnings (thus it's hard to fix things).

I moved away from having a "new" method for PatchEvent
with a series of Strings (which could be confused in order)
and instead am now using just the normal default struct
construction which effectively has named args.

Since EventType is now an enum, it's easy to use the
right enum not have to call PatchInstallEvent::new to
get the right magic string for "identifier".

Also added a bit more documentation to c_api.rs

Description

Type of Change

• ✨ New feature (non-breaking change which adds functionality)
• 🛠️ Bug fix (non-breaking change which fixes an issue)
• ❌ Breaking change (fix or feature that would cause existing functionality to change)
• 🧹 Code refactor
• ✅ Build configuration change
• 📝 Documentation
• 🗑️ Chore

[codecov]

Codecov Report

Patch coverage: 98.00% and project coverage change: -0.07% ⚠️

Comparison is base (292f978) 97.53% compared to head (f85ff52) 97.47%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #77      +/-   ##
==========================================
- Coverage   97.53%   97.47%   -0.07%     
==========================================
  Files           9       10       +1     
  Lines        1864     1858       -6     
==========================================
- Hits         1818     1811       -7     
- Misses         46       47       +1     

Files Changed	Coverage Δ
library/src/c_api.rs	99.49% <ø> (ø)
library/src/events.rs	90.90% <90.90%> (ø)
library/src/network.rs	98.96% <100.00%> (-0.06%)	⬇️

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