Refactor sdk and cli.

[IHosseini083]

Change Summary

• Remove redundant list comprehensions from constants since the str.join() method takes an Iterable as first argument and dict.keys() also returns a set-like object, therefore it's iterable!

For example this

THEMES_HINT = f'''theme (available themes:
{", ".join([_ for _ in THEMES.keys()])})
'''

will become this

THEMES_HINT = f'''theme (available themes:
{", ".join(THEMES.keys())})
'''

• Fix a typo in module docs:

python -mpasteme_cli corrected to python -m pasteme_cli

• Add type annotations for methods and functions.
• Turn Snippet class into a more concise and user friendly interface with more meaningful method names and instance attributes.
• Add new types to represent responses from PasteMe API and give users a pythonic way of accessing response parameters using the dot notation. e.g:

from pasteme_cli.sdk import PasteMe

context = {
    "title": "My Snippet",
    ...
}

snippet = PasteMe(verbose=True).create(**context)
print(snippet.url)

Checklist

• My code follows the style guidelines of this project.
• I have performed a self-review of my own code.
• I have written/changed corresponding tests for new implementations.

[lnxpy]

They look awesome to me! Thank you Iliya jan. So many cool refactors. :))