Update dist package structure

[shorodilov]

Summary

The structures of the development package should be implemented as follows:

/dist
|-- assets/
|   |-- css/
|   |-- fonts/
|   |-- icons/
|   |-- img/
|   `-- js/
`-- templates/
    |-- profile.html
    |-- signin.html
    |-- signup.html
    |-- task_detail.html
    |-- task_form.html
    `-- task_list.html