[bugfix] Allow self-boosting for any visibility but direct (#510)

* create visibility filter for boostability and allow self-boosting for any visbility but direct messages

* add a followers-only status to local_account_2

* fix typo in comment

* add license header, unwrap errors, be explicit about non-boostable visibility settings to avoid rogue boosting from miscoded clients, use ID compare for checking if self-boosting

* add tests for statusboostable filter

* fix tests that were affected by adding a new status to the test data

* fix the rest of tests affected by adding a status to the textrig data

testrig/testmodels.go

@@ -1263,6 +1263,30 @@ func NewTestStatuses() map[string]*gtsmodel.Status {
 			Likeable:                 true,
 			ActivityStreamsType:      ap.ObjectNote,
 		},
+		"local_account_2_status_7": {
+			ID:                       "01G20ZM733MGN8J344T4ZDDFY1",
+			URI:                      "http://localhost:8080/users/1happyturtle/statuses/01G20ZM733MGN8J344T4ZDDFY1",
+			URL:                      "http://localhost:8080/@1happyturtle/statuses/01G20ZM733MGN8J344T4ZDDFY1",
+			Content:                  "🐢 hi followers! did u know i'm a turtle? 🐢",
+			AttachmentIDs:            []string{},
+			CreatedAt:                time.Now().Add(-1 * time.Minute),
+			UpdatedAt:                time.Now().Add(-1 * time.Minute),
+			Local:                    true,
+			AccountURI:               "http://localhost:8080/users/1happyturtle",
+			AccountID:                "01F8MH5NBDF2MV7CTC4Q5128HF",
+			InReplyToID:              "",
+			BoostOfID:                "",
+			ContentWarning:           "",
+			Visibility:               gtsmodel.VisibilityFollowersOnly,
+			Sensitive:                false,
+			Language:                 "en",
+			CreatedWithApplicationID: "01F8MGYG9E893WRHW0TAEXR8GJ",
+			Federated:                true,
+			Boostable:                true,
+			Replyable:                true,
+			Likeable:                 true,
+			ActivityStreamsType:      ap.ObjectNote,
+		},
 		"remote_account_1_status_1": {
 			ID:                       "01FVW7JHQFSFK166WWKR8CBA6M",
 			URI:                      "http://fossbros-anonymous.io/users/foss_satan/statuses/01FVW7JHQFSFK166WWKR8CBA6M",