remove "guide-" from folder names.

[luizcmarin]

remove "guide-" from folder names. I believe this is out of the norm

What is the expected result?

follow the normal pattern for translation folders

[samdark]

This is close to our current standard https://github.com/yiisoft/docs/blob/master/014-docs.md Worth thinking about though.

[vjik]

We use another structure in other packages.

For example, in validator: docs/{type}/{language}: https://github.com/yiisoft/validator/tree/master/docs/guide

[samdark]

Hmm… let's do it in a uniform way. https://github.com/yiisoft/validator/tree/master/docs/guide looks good.