Resolve #3213817: authorization mechanism based on AWS4-HMAC-SHA256.
Issue #3213817.
- implements the authorization mechanism based on AWS4-HMAC-SHA256
- adds a support of the public:// and private:// schemes
The D8 module's version was used as a reference to build a correct signature for a request. The module was tested on the Pantheon: 300 Mb file was uploaded as a public:// without any warnings.