tt: added tt create module

[psergee]

tt create allows a user to create tarantool application from a template.
tt create accepts template name as a parameter and searches for it in

  templates:
    - path:
    - path:

of current environment. Found template will be used for application creation.
'basic' is the default template name.
Supported flags:

FLAGS
  -f, --force              Force rewrite application directory if already exists
  -h, --help               help for create
      --name string        Application name
  -s, --non-interactive    Non-interactive mode
      --var stringArray    Variable definition. Usage: --var var_name=value
      --vars-file string   Variables definition file path

Invocation example:
tt create --var name=name --name=app1 --non-interactive

Closes #12

[vr009]

The code looks good. It would be also nice to have some description how to use it for users, but I don'y know if we have some place to leave the instructions for this. I will leave more feedback for the code later.

[vr009]

It is also accepted (here) to mark a commit with closes #N instead of resolves.

[psergee]

The code looks good. It would be also nice to have some description how to use it for users, but I don'y know if we have some place to leave the instructions for this. I will leave more feedback for the code later.

Examples are added to the help:

EXAMPLES
  
# Create an application from basic template.

    $ tt create

# Create app1 application from cartridge template, set user_name value,
# force replacing of application directory (app1) if it exists. User interaction is disabled.

    $ tt create cartridge --name=app1 --var user_name=admin -f --non-interactive

[0x501D]

LGTM

[vr009]

LGTM
upd. after rebase :)

[LeonidVas]

Hi. I briefly reviewed the patch and plan to explore it further. The idea of using the "chain of responsibility" pattern looks interesting.
I have several comments:

• "Update cartridge-cli submodule" -> "cartridge cli: bump new version".
• It would be nice to add reasons to bump the new version to commit message. I think this was done not just for fun.

[LeonidVas]

Hi! Thank you for the patchset.
Patchset already has two LGTM so I did not see it in detail, rather an introductory one.
I expect the following PR with a description of the functionality in the README and with examples in https://github.com/tarantool/tt/blob/master/doc/examples.rst

Fix typos in code and comment -> Commit title should be of a form <subsystem>: <description> (https://github.com/tarantool/tarantool/wiki/Code-review-procedure#commit-message)

This is a big and good work, and I believe that in the future you will split the functionality into several commits. Right now it's very difficult to review.

See comments bellow (some of them may be irrelevant because your update happened in the middle of my review.).

[LeonidVas]

Perhaps some of the questions are easier to discuss by voice. So ping if you need.