Add get_log_level and set_log_level operations to the app route (#3858)

## What type of PR is this? (check all applicable)

- [ ] Refactor
- [ X] Feature
- [ ] Bug Fix
- [ ] Optimization
- [ ] Documentation Update
- [ ] Community Node Submission


## Have you discussed this change with the InvokeAI team?
- [X ] Yes
- [ ] No, because:

      
## Have you updated relevant documentation?
- [ X] Yes (swagger)
- [ ] No


## Description

This add new routes for getting and setting the command line console
logging level.

invokeai/app/api/routers/app_info.py

@@ -1,9 +1,22 @@
+from enum import Enum
+from fastapi import Body
 from fastapi.routing import APIRouter
 from pydantic import BaseModel, Field
 
 from invokeai.backend.image_util.patchmatch import PatchMatch
 from invokeai.version import __version__
 
+from ..dependencies import ApiDependencies
+from invokeai.backend.util.logging import logging
+
+class LogLevel(int, Enum):
+    NotSet = logging.NOTSET
+    Debug = logging.DEBUG
+    Info = logging.INFO
+    Warning = logging.WARNING
+    Error = logging.ERROR
+    Critical = logging.CRITICAL
+    
 app_router = APIRouter(prefix="/v1/app", tags=["app"])
 
 
@@ -34,3 +47,27 @@ async def get_config() -> AppConfig:
     if PatchMatch.patchmatch_available():
         infill_methods.append('patchmatch')
     return AppConfig(infill_methods=infill_methods)
+
+@app_router.get(
+    "/logging",
+    operation_id="get_log_level",
+    responses={200: {"description" : "The operation was successful"}},
+    response_model = LogLevel,
+)
+async def get_log_level(
+) -> LogLevel:
+    """Returns the log level"""
+    return LogLevel(ApiDependencies.invoker.services.logger.level)
+
+@app_router.post(
+    "/logging",
+    operation_id="set_log_level",
+    responses={200: {"description" : "The operation was successful"}},
+    response_model = LogLevel,
+)
+async def set_log_level(
+        level: LogLevel = Body(description="New log verbosity level"),
+) -> LogLevel:
+    """Sets the log verbosity level"""
+    ApiDependencies.invoker.services.logger.setLevel(level)
+    return LogLevel(ApiDependencies.invoker.services.logger.level)