[lora] add lora APIs for booster, support lora for TorchDDP (#4981)

* add apis and peft requirement

* add liscense and implement apis

* add checkpointio apis

* add torchddp fwd_bwd test

* add support_lora methods

* add checkpointio test and debug

* delete unneeded codes

* remove peft from LICENSE

* add concrete methods for enable_lora

* simplify enable_lora api

* fix requirements

colossalai/booster/plugin/plugin_base.py

@@ -1,5 +1,5 @@
 from abc import ABC, abstractmethod
-from typing import Callable, Iterator, List, Optional, Tuple
+from typing import Callable, Dict, Iterator, List, Optional, Tuple
 
 import torch.nn as nn
 from torch.optim import Optimizer
@@ -33,6 +33,10 @@ class Plugin(ABC):
     def support_no_sync(self) -> bool:
         pass
 
+    @abstractmethod
+    def support_lora(self) -> bool:
+        pass
+
     @abstractmethod
     def configure(
         self,
@@ -63,6 +67,12 @@ class Plugin(ABC):
         Context manager to disable gradient synchronization.
         """
 
+    @abstractmethod
+    def enable_lora(self, model: nn.Module, pretrained_dir: str, lora_config: Dict) -> nn.Module:
+        """
+        Add LoRA modules to the model passed in. Should only be called in booster.enable_lora().
+        """
+
     @abstractmethod
     def prepare_dataloader(
         self,