Implement basic features with structured layer

[hexoul]

Motivation:

• Initial commit to make Central Dogma client in Python

Modifications:

`Dogma` ---------- `ProjectService` ----------- `BaseClient`
              |                           |
              ---- `RepositoryService` ----
              |                           |
              ---- `ContentService` -------

• Implemented synchronous features are as follows:
  • ProjectService
    • List projects
    • Create a project
    • Remove a project
    • Unremove a project
    • Purge a project
  • RepositoryService
    • List repositories
    • Create a repository
    • Remove a repository
    • Unremove a repository
    • Purge a repository
    • Normalize a repository revision
  • ContentService
    • List files
    • Get files
    • Get a file

Result:

• Above features are available.
• Examples.
• README.

[ikhoon]

The basic structure looks good to me.

[ikhoon]

Thanks! @hexoul Let's move on to the next stage!

[minwoox]

Thanks! Left some questions and minor comments. 😄

[minwoox]

Thanks! just nits. 😄

[minwoox]

only _request() depends on requests, not request()

Yeah but, the return type of request() is requests.Response so it still depends on it?

[minwoox]

Thanks a lot @hexoul, I learned a lot. 😄

[minwoox]

Suggested change

	return self.base_url + "/" + self.PATH_PREFIX + path
	return self.base_url + self.PATH_PREFIX + path

Let's do this and do
PATH_PREFIX = "/api/v1"

[minwoox]

Also we might want to normalize the base_url later because if base_url endswith / then there are double /s. 😄

[hexoul]

Thanks! Good point. I did workaround in constructor to prevent from being double /s. Please check it. https://github.com/line/centraldogma-python/pull/1/files#diff-50828eb36eff8f9de6017b747f7ba14ff8d5ecda0f1f528ee180f3e44574ba6bR24

>>> a = "123/"
>>> a[-1]
'/'
>>> a[:-1]
'123'

[minwoox]

Awesome. 👍

[minwoox]

@okue Do you have a chance to look at this PR?
If you don't have time, then I think we can just merge this and implement the next feature. 😄

[minwoox]

🎉 🎉 🎉
Thanks a lot @hexoul!
Let's go on to the next stage. 😄