Rename all decorators to lowercase

[the-owl]

Renamed all decorators to lowercase according to issue #596

Description

All decorators have been just renamed to lowercase, with the expection of HTTP method decorators - these have been prefixed with http because delete is a reserved word and it cannot be used as an identifier. So new names are httpGet, httpPost, ..., etc.
Also, decorators in unit tests have been renamed and import name of supertest library has been changed from request to supertest to avoid name collision with @request decorator.
Documentation (README.md) has been updated to match new decorator names.

Related Issue

inversify/InversifyJS#596

How Has This Been Tested?

All unit tests pass successfully.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes (because no code has been added).
• All new and existing tests passed.

[remojansen]

@the-owl thanks a lot for contributing 👍 I hope you enjoyed it :)