Use sync handlers instead of async handlers (#17)

We've been getting a lot of errors in the upload endpoint:
```
curl: (22) The requested URL returned error: 504
```


https://github.com/WATonomous/infra-config/actions/runs/12575927900/job/35051479296

This may be caused by too many clients trying to upload at the same
time. This PR changes all of the handlers to sync handlers in attempt to
alleviate this problem.

server/src/main.py

@@ -149,7 +149,7 @@ async def fastapi_lifespan(app: FastAPI):
 transaction_lock = Lock()
 
 @fastapi_app.post("/repos/{repo_name}")
-async def upload(
+def upload(
     repo_name: str,
     file: UploadFile,
     unpack: bool = False,
@@ -191,7 +191,7 @@ async def upload(
             else:
                 # Upload file
                 with dest.open("wb") as f:
-                    f.write(await file.read())
+                    f.write(file.file.read())
 
             upload_end = time.perf_counter()
 
@@ -227,7 +227,7 @@ async def upload(
 
 @app.command()
 @fastapi_app.post("/repos/{repo_name}/{file_name}/ttl")
-async def update_ttl(repo_name: str, file_name: str, ttl_s: int):
+def update_ttl(repo_name: str, file_name: str, ttl_s: int):
     logger.info(f"Updating TTL for file: {file_name} in repo: {repo_name}")
 
     if file_name in PATH_BLACKLIST:
@@ -266,7 +266,7 @@ async def update_ttl(repo_name: str, file_name: str, ttl_s: int):
 
 @app.command()
 @fastapi_app.get("/repos/{repo_name}/{file_name}")
-async def download(repo_name: str, file_name: str):
+def download(repo_name: str, file_name: str):
     logger.info(f"Downloading file: {file_name} from repo: {repo_name}")
 
     file_path = Path(f"/cvmfs/{repo_name}/{file_name}")
@@ -277,7 +277,7 @@ async def download(repo_name: str, file_name: str):
 
 @app.command()
 @fastapi_app.get("/repos/{repo_name}")
-async def list_files(repo_name: str):
+def list_files(repo_name: str):
     logger.info(f"Listing files in repo: {repo_name}")
 
     repo_path = Path(f"/cvmfs/{repo_name}")
@@ -288,7 +288,7 @@ async def list_files(repo_name: str):
 
 @app.command()
 @fastapi_app.delete("/repos/{repo_name}/{target_name}")
-async def delete(repo_name: str, target_name: str):
+def delete(repo_name: str, target_name: str):
     logger.info(f"Deleting target: `{target_name}` from repo: `{repo_name}`")
 
     if target_name in PATH_BLACKLIST: