Implement major enhancements to plugin manager (v1.2.0 & v1.3.0)

This commit introduces significant improvements and new features to the plugin manager:

- Add plugin discovery system and remote repository support
- Implement plugin update system with digital signature verification
- Enhance plugin lifecycle hooks (PreLoad, PostLoad, PreUnload)
- Improve dependency management with custom version comparison
- Introduce lazy loading for optimized plugin performance
- Implement comprehensive error handling and logging
- Enhance concurrency safety with fine-grained locking
- Add plugin statistics tracking
- Remove external version comparison dependencies
- Improve hot-reload functionality with graceful shutdown
- Add SSH key support for remote repositories
- Implement Redbean server integration for plugin repositories

This update significantly improves the plugin manager's functionality,
security, and performance, providing a more robust and flexible system
for managing plugins in Go applications.

examples/plugins/hello/hello.go

@@ -2,29 +2,27 @@ package main
 
 import (
     "fmt"
+
     pm "github.com/matt-dunleavy/plugin-manager"
 )
 
-type HelloPlugin struct {
-    greeting string
-}
+type HelloPlugin struct{}
 
 func (p *HelloPlugin) Metadata() pm.PluginMetadata {
     return pm.PluginMetadata{
-        Name:         "HelloPlugin",
-        Version:      "1.0.0",
-        Dependencies: []string{},
+        Name:    "HelloPlugin",
+        Version: "1.0.0",
+        Dependencies: map[string]string{},
     }
 }
 
 func (p *HelloPlugin) Init() error {
-    p.greeting = "Hello, World!"
     fmt.Println("HelloPlugin initialized")
     return nil
 }
 
 func (p *HelloPlugin) Execute() error {
-    fmt.Println(p.greeting)
+    fmt.Println("Hello from HelloPlugin!")
     return nil
 }
 
@@ -33,4 +31,19 @@ func (p *HelloPlugin) Shutdown() error {
     return nil
 }
 
+func (p *HelloPlugin) PreLoad() error {
+    fmt.Println("HelloPlugin pre-load")
+    return nil
+}
+
+func (p *HelloPlugin) PostLoad() error {
+    fmt.Println("HelloPlugin post-load")
+    return nil
+}
+
+func (p *HelloPlugin) PreUnload() error {
+    fmt.Println("HelloPlugin pre-unload")
+    return nil
+}
+
 var Plugin HelloPlugin