Format change url and fileName.

GetObject return Name object will be in format `username/filename` as standard format in upload file.

map http header to file header return new map and key is lowercase.

should guarantee metadata use lowercase as file header follow HTTP 2.0 standard.

UploadObject filePath must be in format `username/filename`.

Since HTTP 1.1 is case insensitive, but we follow HTTP 2.0 standard which is lowercase.

Since HTTP 1.1 is case insensitive, but we follow HTTP 2.0 standard which is lowercase.

Since HTTP 1.1 is case insensitive, but we follow HTTP 2.0 standard which is lowercase.

Since HTTP 1.1 is case insensitive, but we follow HTTP 2.0 standard which is lowercase.

Since HTTP 1.1 is case insensitive, but we follow HTTP 2.0 standard which is lowercase.