Use admin instead of public folder for plugins

packages/strapi-admin/files/controllers/Admin.js

@@ -20,7 +20,7 @@ module.exports = {
 
   pluginFile: async ctx => {
     try {
-      const file = fs.readFileSync(path.resolve(process.cwd(), 'plugins', ctx.params.plugin, 'public', 'build', 'main.js'));
+      const file = fs.readFileSync(path.resolve(process.cwd(), 'plugins', ctx.params.plugin, 'admin', 'build', 'main.js'));
       ctx.body = file;
     } catch (err) {
       ctx.body = ctx.notFound();

packages/strapi/lib/configuration/hooks/dictionary/_config/index.js

@@ -111,7 +111,7 @@ module.exports = strapi => {
         'plugins/**': cb => {
           dictionary.optional({
             dirname: path.resolve(strapi.config.appPath, strapi.config.paths.plugins),
-            excludeDirs: /(public)$/,
+            excludeDirs: /(public|admin)$/,
             filter: /(.+)\.(js|json)$/,
             depth: 4
           }, cb);