feat(plugins): Implement event system w/ POC events

Implements the partially created event system with 3 events implemented as proof of concepts.

The 3 events are:
- `blacklistedIpBlocked`: emitted when a request from a blacklisted IP
- `accessRuleCreated`: emitted when a new access rule is created
- `blacklistToggled`: emitted when the blacklist is toggled for a given access rule

Why these events? Because these are the ones I forsee myself needing in the next version of the zoraxy_crowdsec_bouncer

Events are dispatched via a global event manager `plugins.EventSystem.Emit`

src/mod/dynamicproxy/access.go

@@ -7,6 +7,8 @@ import (
 
 	"imuslab.com/zoraxy/mod/access"
 	"imuslab.com/zoraxy/mod/netutils"
+	"imuslab.com/zoraxy/mod/plugins"
+	"imuslab.com/zoraxy/mod/plugins/zoraxy_plugin"
 )
 
 // Handle access check (blacklist / whitelist), return true if request is handled (aka blocked)
@@ -43,6 +45,23 @@ func accessRequestBlocked(accessRule *access.AccessRule, templateDirectory strin
 			w.Write(template)
 		}
 
+		// Emit blacklisted IP blocked event
+		// Get the comment for this IP
+		comment, err := accessRule.GetBlacklistedIPComment(clientIpAddr)
+		if err != nil {
+			comment = "blacklisted"
+		}
+		plugins.EventSystem.Emit(
+			&zoraxy_plugin.BlacklistedIPBlockedEvent{
+				IP:           clientIpAddr,
+				Comment:      comment,
+				RequestedURL: r.URL.String(),
+				Hostname:     r.Host,
+				UserAgent:    r.Header.Get("User-Agent"),
+				Method:       r.Method,
+			},
+		)
+
 		return true, "blacklist"
 	}