Improved hooks monitoring

...to work for specific edge cases with a simpler solution.
Re-reads hooks directories after any changes are detected by the watchers.
Added monitoring test for adding a different invalid hook to primary directory.
Some issues with prior code:
- ReadDir would stop when it encounters an invalid hook, rather than registering an error but continuing to read the valid hook.
- Wouldn’t account for Rename and Chmod events.
- After doing a mv of the hooks file instead of rm, it would still think the hooks file is in the directory, but it has been moved to another location.
- If a hook file was renamed, it would register the renamed file as a separate hook and not delete the original, so it would then execute the hook twice - once for the renamed file, and once for the original name which it did not delete.

Signed-off-by: samc24 <sam.chaturvedi24@gmail.com>

pkg/hooks/hooks.go

@@ -4,7 +4,6 @@ package hooks
 import (
 	"context"
 	"fmt"
-	"path/filepath"
 	"sort"
 	"strings"
 	"sync"
@@ -138,26 +137,3 @@ func (m *Manager) Hooks(config *rspec.Spec, annotations map[string]string, hasBi
 
 	return extensionStageHooks, nil
 }
-
-// remove remove a hook by name.
-func (m *Manager) remove(hook string) (ok bool) {
-	m.lock.Lock()
-	defer m.lock.Unlock()
-	_, ok = m.hooks[hook]
-	if ok {
-		delete(m.hooks, hook)
-	}
-	return ok
-}
-
-// add adds a hook by path
-func (m *Manager) add(path string) (err error) {
-	m.lock.Lock()
-	defer m.lock.Unlock()
-	hook, err := Read(path, m.extensionStages)
-	if err != nil {
-		return err
-	}
-	m.hooks[filepath.Base(path)] = hook
-	return nil
-}