Fix GenerationStrategy and GenerataionNode todos (#330)

Summary:
X-link: facebook/Ax#2142

Pull Request resolved: #330

In this diff we update the Ax GenerationStrategy code to remove all todos related to aepsych, and use the standard GS code flow for aepsych usecases. This required some minimal updates to the aepsych criterion and one of the storage tests.

In following diffs we will:
- revisit storage
- update AEPsych GSs as needed
- determine if run indefinetly can be replaced by simply having gen_unlimited_trials = true

Reviewed By: lena-kashtelyan

Differential Revision: D52898268

fbshipit-source-id: 4cc98b100c26aed052322f13ae103455733e1606

aepsych/generators/completion_criterion/min_asks.py

@@ -14,10 +14,21 @@
 
 
 class MinAsks(TransitionCriterion, ConfigurableMixin):
-    def __init__(self, threshold: int) -> None:
+    def __init__(
+        self,
+        threshold: int,
+        block_transition_if_unmet: Optional[bool] = True,
+        block_gen_if_met: Optional[bool] = False,
+    ) -> None:
         self.threshold = threshold
-
-    def is_met(self, experiment: Experiment) -> bool:
+        super().__init__(
+            block_transition_if_unmet=block_transition_if_unmet,
+            block_gen_if_met=block_gen_if_met,
+        )
+
+    def is_met(
+        self, experiment: Experiment, trials_from_node: Optional[Set[int]] = None
+    ) -> bool:
         return experiment.num_asks >= self.threshold
 
     def block_continued_generation_error(
@@ -32,5 +43,7 @@ def block_continued_generation_error(
     @classmethod
     def get_config_options(cls, config: Config, name: str) -> Dict[str, Any]:
         min_asks = config.getint(name, "min_asks", fallback=1)
-        options = {"threshold": min_asks}
+        options = {
+            "threshold": min_asks,
+        }
         return options

aepsych/generators/completion_criterion/run_indefinitely.py

@@ -13,10 +13,19 @@
 
 
 class RunIndefinitely(TransitionCriterion, ConfigurableMixin):
-    def __init__(self, run_indefinitely: bool) -> None:
+    def __init__(
+        self,
+        run_indefinitely: bool,
+        block_transition_if_unmet: Optional[bool] = False,
+        block_gen_if_met: Optional[bool] = False,
+    ) -> None:
         self.run_indefinitely = run_indefinitely
+        self.block_transition_if_unmet = block_transition_if_unmet
+        self.block_gen_if_met = block_gen_if_met
 
-    def is_met(self, experiment: Experiment) -> bool:
+    def is_met(
+        self, experiment: Experiment, trials_from_node: Optional[Set[int]] = None
+    ) -> bool:
         return not self.run_indefinitely
 
     def block_continued_generation_error(