Webcode generator

- Added console command to generate webcodes for articles based on article number. Each webcode will be unique.
- Removed old way to generate webcodes

Usage:
```
php application/console webcode:generate <article_number_start_range>
```
`<article_number_start_range>` - is integer value e.g. 300. If defined, webcodes will be generated for articles that have number more than 300.