expose supervisor tasks that are fully self-contained fuzzing tasks in the service (#474)

Exposes the functionality added in #454 to the service & CLI.

Fixes #439

src/pytypes/onefuzztypes/enums.py

@@ -57,6 +57,7 @@ class TaskFeature(Enum):
     stats_file = "stats_file"
     stats_format = "stats_format"
     target_exe = "target_exe"
+    target_exe_optional = "target_exe_optional"
     target_env = "target_env"
     target_options = "target_options"
     analyzer_exe = "analyzer_exe"

src/pytypes/onefuzztypes/models.py

@@ -142,9 +142,9 @@ class ReproConfig(BaseModel):
 class TaskDetails(BaseModel):
     type: TaskType
     duration: int
-    target_exe: str
-    target_env: Dict[str, str]
-    target_options: List[str]
+    target_exe: Optional[str]
+    target_env: Optional[Dict[str, str]]
+    target_options: Optional[List[str]]
     target_workers: Optional[int]
     target_options_merge: Optional[bool]
     check_asan_log: Optional[bool]