change form json format of some endpoints, add BC to some

all POST endpoints now return 400 responses with a body like this:
`{"error":{"key":"value",...}}`

Author: ornicar

app/controllers/Analyse.scala

@@ -160,7 +160,7 @@ final class Analyse(
       lila.analyse.ExternalEngine.form
         .bindFromRequest()
         .fold(
-          err => badJsonFormError(err),
+          jsonFormError,
           data =>
             env.analyse.externalEngine.create(me, data, tokenId.value) map { engine =>
               Created(lila.analyse.ExternalEngine.jsonWrites.writes(engine))
@@ -175,7 +175,7 @@ final class Analyse(
         lila.analyse.ExternalEngine.form
           .bindFromRequest()
           .fold(
-            err => badJsonFormError(err),
+            jsonFormError,
             data =>
               env.analyse.externalEngine.update(engine, data) map { engine =>
                 JsonOk(lila.analyse.ExternalEngine.jsonWrites.writes(engine))

app/controllers/BulkPairing.scala

@@ -30,7 +30,7 @@ final class BulkPairing(env: Env) extends LilaController(env):
     lila.setup.SetupBulk.form
       .bindFromRequest()
       .fold(
-        badJsonFormError,
+        jsonFormError,
         data =>
           env.setup.bulk(data, me) flatMap {
             case Left(SetupBulk.ScheduleError.RateLimited) =>

app/controllers/Challenge.scala

@@ -161,7 +161,7 @@ final class Challenge(
         env.challenge.forms.decline
           .bindFromRequest()
           .fold(
-            badJsonFormError,
+            jsonFormError,
             data => api.decline(c, data.realReason) inject jsonOkResult
           )
     }
@@ -282,7 +282,7 @@ final class Challenge(
       !me.is(username) so env.setup.forms.api.user
         .bindFromRequest()
         .fold(
-          badJsonFormError,
+          doubleJsonFormError,
           config =>
             ChallengeIpRateLimit(req.ipAddress, rateLimitedFu, cost = if me.isApiHog then 0 else 1):
               env.user.repo enabledById username flatMap {

app/controllers/Setup.scala

@@ -188,7 +188,7 @@ final class Setup(
               ctx.isMobileOauth || (ctx.isAnon && HTTPRequest.isLichessMobile(ctx.req))
             .bindFromRequest()
             .fold(
-              badJsonFormError,
+              doubleJsonFormError,
               config =>
                 ctx.me.so(env.relation.api.fetchBlocking(_)).flatMap { blocking =>
                   val uniqId = author.fold(_.value, u => s"sri:${u.id}")

app/controllers/Swiss.scala

@@ -196,7 +196,7 @@ final class Swiss(
           err =>
             negotiate(
               BadRequest.page(html.swiss.form.edit(swiss, err)),
-              badJsonFormError(err)
+              jsonFormError(err)
             ),
           data =>
             env.swiss.api.update(swiss.id, data) >> negotiate(
@@ -215,8 +215,8 @@ final class Swiss(
           .bindFromRequest()
           .fold(
             err =>
-              render.async:
-                case Accepts.Json() => badJsonFormError(err)
+              render.async: // TODO
+                case Accepts.Json() => jsonFormError(err)
                 case _              => Redirect(routes.Swiss.show(id))
             ,
             date =>

app/controllers/Team.scala

@@ -271,7 +271,7 @@ final class Team(
               .apiRequest(team)
               .bindFromRequest()
               .fold(
-                badJsonFormError,
+                jsonFormError,
                 setup =>
                   api.join(team, setup.message, setup.password) flatMap {
                     case Requesting.Joined       => jsonOkResult

app/controllers/Tournament.scala

@@ -309,7 +309,7 @@ final class Tournament(env: Env, apiC: => Api)(using mat: akka.stream.Materializ
             .edit(teams, tour)
             .bindFromRequest()
             .fold(
-              badJsonFormError,
+              jsonFormError,
               data =>
                 api.apiUpdate(tour, data) flatMap { tour =>
                   jsonView(
@@ -374,7 +374,7 @@ final class Tournament(env: Env, apiC: => Api)(using mat: akka.stream.Materializ
         lila.tournament.TeamBattle.DataForm.empty
           .bindFromRequest()
           .fold(
-            badJsonFormError,
+            jsonFormError,
             res =>
               api.teamBattleUpdate(tour, res, env.team.api.filterExistingIds) >> {
                 cachedTour(tour.id) map (_ | tour) flatMap { tour =>