Guild A/B test and Achievement (#8740)

* WIP(guilds): AB test pester modal

* WIP(AB-test): guild pester cont'd

* fix(style): linting error

* fix(AB-test): markModified and notif enum

* fix(tests): update AB expectations

* fix(modal): remove extra includes

* feat(achievements): add Joined Guild cheevo
Also removes unused achievement sprites, and properly saves counter used in A/B testing

* fix(style): linting error from conflict

website/server/models/user/schema.js

@@ -112,6 +112,7 @@ let schema = new Schema({
     partyUp: Boolean,
     partyOn: Boolean,
     royallyLoyal: Boolean,
+    joinedGuild: Boolean,
   },
 
   backer: {
@@ -545,7 +546,6 @@ let schema = new Schema({
     return {};
   }},
   pushDevices: [PushDeviceSchema],
-  _ABtest: {type: String}, // deprecated. Superseded by _ABtests
   _ABtests: {type: Schema.Types.Mixed, default: () => {
     return {};
   }},