Migrating away from the notion of public/private URL in WorkAdventure Github repository

The notion of public/private repositories (with /_/ and /@/ URLs) is specific to the SAAS version of WorkAdventure.
It would be better to avoid leaking the organization/world/room structure of the private SAAS URLs inside the WorkAdventure Github project.

Rather than sending http://admin_host/api/map?organizationSlug=...&worldSlug=...&roomSlug=...., we are now sending /api/map&playUri=...
where playUri is the full URL of the current game.
This allows the backend to act as a complete router.
The front (and the pusher) will be able to completely ignore the specifics of URL building (with /@/ and /_/ URLs, etc...)
Those details will live only in the admin server, which is way cleaner (and way more powerful).

maps/Floor1/floor1.json

@@ -1,11 +1,4 @@
 { "compressionlevel":-1,
- "editorsettings":
-    {
-     "export":
-        {
-         "target":"."
-        }
-    },
  "height":26,
  "infinite":false,
  "layers":[
@@ -101,7 +94,7 @@
          "opacity":1,
          "properties":[
                 {
-                 "name":"exitSceneUrl",
+                 "name":"exitUrl",
                  "type":"string",
                  "value":"\/@\/tcm\/workadventure\/floor2#down-the-stairs"
                 }],
@@ -119,7 +112,7 @@
          "opacity":1,
          "properties":[
                 {
-                 "name":"exitSceneUrl",
+                 "name":"exitUrl",
                  "type":"string",
                  "value":"\/@\/tcm\/workadventure\/floor2#down-the-stairs-secours"
                 }],
@@ -264,7 +257,7 @@
  "nextobjectid":1,
  "orientation":"orthogonal",
  "renderorder":"right-down",
- "tiledversion":"1.3.3",
+ "tiledversion":"2021.03.23",
  "tileheight":32,
  "tilesets":[
         {
@@ -1959,6 +1952,6 @@
         }],
  "tilewidth":32,
  "type":"map",
- "version":1.2,
+ "version":1.5,
  "width":46
 }