[Translations: /sv] Swedish translation

Started translation into swedish. Anyone's welcome to jump in.

## Progress

 - [x] _config.yml
 - [x] sv/index.html

#### Installation
 - [x] sv/installation/deploy.md
 - [x] sv/installation/index.md
 - [ ] sv/installation/linux.md
 - [ ] sv/installation/mac.md
 - [ ] sv/installation/troubleshooting.md
 - [ ] sv/installation/upgrading.md
 - [ ] sv/installation/windows.md

#### Quickstart, Themes & Mail
 - [ ] sv/quickstart/quickstart.md
 - [ ] sv/mail/index.md
 - [ ] sv/themes/index.md

#### Usage
 - [ ] sv/usage/index.md
 - [ ] sv/usage/configuration.md
 - [ ] sv/usage/faq.md
 - [ ] sv/usage/index.md
 - [ ] sv/usage/managing.md
 - [ ] sv/usage/settings.md
 - [ ] sv/usage/writing.md