Migration to Vuejs version 2

List of required changes for our Vue usages 

- `init` ➡ `beforeCreate`
- `read` ➡ `mounted`
- `$els` ➡ `$refs`
- 🚫 `$remove` completely removed. ✅ Use `indexOf` and `splice`
- 🚫 HTML embedding with `{{{ }}}` is deprecated. ✅ Use `v-html`


See merge request !7254