Py-imports

Added
- The possibility to know if the imports are located inside inner scope ex. `function`, `class`, etc.
- Attribute `in_inner_scope` in every concrete class (`AbsoluteImportStatement`, `RelativeImportStatement`, `ImportFromStatement`)
to identify import inside a inner scope
- Attribute `outer_parent_node` that will contain the `AST` node referencing the structure that is around the import located in an inner scope.

Added
- Add new classifiers in order to index the pypi package
- `Topic :: Utilities`
- ` Topic :: Software Development :: Libraries`
- `Operating System :: Microsoft :: Windows`
- `Operating System :: MacOS :: MacOS X`
- `Operating System :: POSIX`

- Feature examples in README.md documentation in order to show the assumptions taken to build the util and how to use it

Added
- CHANGELOG to track notable changes
- Metadata about unused imports in the concrete implementations (`AbsoluteImportStatement`, `RelativeImportStatement`, `ImportFromStatement`)

Fixed
- Avoid silencing exceptions in `PyImports` context manager

Added

- Collector object `ImportsCollectionFile` to abstract the information about imports in the file
- `AbsoluteImportStatement`, `RelativeImportStatement`, `ImportFromStatement` concrete classes to describe each of the import types
- `AstImportAnalyzer` to traverse the abstract syntax tree python code
- Context manager `PyImports` to introspect imports in a file | directory