Remove convention where Async suffix is added to functions that returns
a Promise. It was a habit from C#, but is not widely used in JavaScript
/ TypeScript world, also bloats the code. The code is more consistent
with third party dependencies/frameworks without the suffix.
Alias would remove unnecessary repetitions and less relative paths make changes easier when moving around files. This commit cleans also up some relative paths ('../../../') by using the alias and orders imports. It updates both path alias in tsconfig and module alias in Vue CLI's bundler (vuejs/vue-cli#2398).