fix(graphql): set not nullable values on members and add type docs for teams

BREAKING CHANGE:
make teamMember id and user in gql not-nullable

src/models/team/team.graphql

 type Team {
+  "The team id"
   id: ID!
+  "The team role (eg. 'editor')"
   role: String!
+  "The team display name"
   displayName: String!
+  "The related object id (only if not global)"
   objectId: ID
+  "The related object type (only if not global)"
   objectType: String
+  "The members of the team"
   members(currentUserOnly: Boolean): [TeamMember!]
+  "Whether the team is global or not"
   global: Boolean!
 }
 

src/models/teamMember/teamMember.graphql

 type TeamMember {
-  id: ID
-  user: User
+  "The team member id"
+  id: ID!
+  "The user related to this team member. Members are separate entities from users."
+  user: User!
+  "The status of the team member"
   status: String
 }