Create deploy playbook

- Add deploy user, set profile and lock it.
- Add profile file.

Fixes #2
Fixes #3
Closes #30
Create git playbook

- Create git user, group, ssh floder.
- Install git-core package.

Fixes #4
Fixes #5
Closes #31
Minor fixes

- /srv owned by deploy group;
Create main site.yml and rearrange files

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Ref #31