removing 4th step - hexo generate

@axil 

I think it's better if we remove the step `hexo generate`, as we don't need to [generate](https://hexo.io/docs/generating.html) the site before [previewing](https://hexo.io/docs/server.html) with `hexo server`. 

We either `hexo generate --watch` or `hexo server` - I don't see why would we do both.

After adding our content, we could generate it, though.

Just my thoughts anyway...

Do you agree?

See merge request !2

Fix layout

Fixes #1 

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Correct paths: url and baseurl

`_config.yml`:

```yaml
url: https://pages.gitlab.io/
root: "/hexo/"
```

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# **Results**

![hexo-pages](/uploads/e7b2379f430a09b4ea184a0c55822fe0/hexo-pages.png)

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Forked build: [passed](https://gitlab.com/virtuacreative/hexo/commit/01f3d994e6f5c23ee645beb7914ce128d87b711b)

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cc/ @axil 


See merge request !1

Fixes https://gitlab.com/pages/hexo/issues/1