refactor: migrate native modules from bauh/ to bearhub/ (test batch)

.gitignore

@@ -22,3 +22,4 @@ AGENTS.md
 packaging/aur/**/*.tar.gz
 packaging/aur/**/src
 packaging/aur/**/pkg
+

bearhub/api/abstract/cache.py

@@ -0,0 +1,50 @@
+from abc import ABC, abstractmethod
+from typing import Set, Optional
+
+
+class MemoryCache(ABC):
+    """
+    Represents a memory cache.
+    """
+
+    @abstractmethod
+    def is_enabled(self):
+        pass
+
+    @abstractmethod
+    def add(self, key: str, val: object):
+        pass
+
+    @abstractmethod
+    def add_non_existing(self, key: str, val: object):
+        pass
+
+    @abstractmethod
+    def get(self, key: str):
+        pass
+
+    @abstractmethod
+    def delete(self, key):
+        pass
+
+    @abstractmethod
+    def keys(self) -> Set[str]:
+        pass
+
+    @abstractmethod
+    def clean_expired(self):
+        pass
+
+
+class MemoryCacheFactory(ABC):
+    """
+    Instantiate new memory cache instances.
+    """
+
+    @abstractmethod
+    def new(self, expiration: Optional[int]) -> MemoryCache:
+        """
+        :param expiration: expiration time for the cache keys in seconds. Use -1 to disable this feature.
+        :return:
+        """
+        pass