feat(preset): adds 2 presets along the default one

Default preset `ts-jest` becomes an alias to `ts-jest/presets/default`
which contains the same as previous `ts-jest` preset. Compilation of js
files can be done using the `ts-jest/presets/js-with-ts` or
`ts-jest/presets/js-with-babel` additional presets.

Author: huafu

jest-preset.js

@@ -1,4 +1 @@
-const createJestPreset = require('./dist/config/create-jest-preset')
-  .createJestPreset
-
-module.exports = createJestPreset()
+module.exports = require('./presets/default/jest-preset')

presets/create.js

@@ -0,0 +1 @@
+module.exports = require('../dist/config/create-jest-preset').createJestPreset

presets/default/jest-preset.js

@@ -0,0 +1,3 @@
+const create = require('../create')
+
+module.exports = create()

presets/js-with-babel/jest-preset.js

@@ -0,0 +1,7 @@
+const create = require('../create')
+
+module.exports = create({ allowJs: false }, {
+  transform: {
+    '^.+\\.jsx?$': 'babel-jest',
+  },
+})

presets/js-with-ts/jest-preset.js

@@ -0,0 +1,3 @@
+const create = require('../create')
+
+module.exports = create({allowJs: true})