MDL-74301 eslint: Upgrade eslint and babel

This patch includes changes:
* Upgrade "@babel/core" to latest point release
* Remove plugins already included into current "@babel/preset-env":
  - "@babel/plugin-proposal-class-properties"
  - "@babel/plugin-proposal-json-strings"
  - "@babel/plugin-syntax-dynamic-import"
  - "@babel/plugin-syntax-import-meta"
* Upgrade "eslint" to latest version
* Replace "eslint-plugin-babel" (depreacted in 2019) with "@babel/eslint-parser" and "@babel/eslint-plugin"

Author: kabalin

.grunt/tasks/javascript.js

@@ -151,11 +151,7 @@ module.exports = grunt => {
                             //
                             // It also adds the Moodle plugin name to the AMD module definition
                             // so that it can be imported as expected in other modules.
-                            path.resolve('.grunt/babel-plugin-add-module-to-define.js'),
-                            '@babel/plugin-syntax-dynamic-import',
-                            '@babel/plugin-syntax-import-meta',
-                            ['@babel/plugin-proposal-class-properties', {'loose': false}],
-                            '@babel/plugin-proposal-json-strings'
+                            path.resolve('.grunt/babel-plugin-add-module-to-define.js')
                         ],
                         presets: [
                             ['@babel/preset-env', {