Update Azure SDK and support additional authentication schemes

Microsoft has updated the golang Azure SDK significantly.  Update the
azure storage driver to use the new SDK.  Add support for client
secret and MSI authentication schemes in addition to shared key
authentication.

Implement rootDirectory support for the azure storage driver to mirror
the S3 driver.

Signed-off-by: Kirat Singh <kirat.singh@beacon.io>

Co-authored-by: Cory Snider <corhere@gmail.com>

vendor/github.com/pkg/browser/zbrowser_windows.go

@@ -0,0 +1,76 @@
+// Code generated by 'go generate'; DO NOT EDIT.
+
+package browser
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+var _ unsafe.Pointer
+
+// Do the interface allocations only once for common
+// Errno values.
+const (
+	errnoERROR_IO_PENDING = 997
+)
+
+var (
+	errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
+	errERROR_EINVAL     error = syscall.EINVAL
+)
+
+// errnoErr returns common boxed Errno values, to prevent
+// allocations at runtime.
+func errnoErr(e syscall.Errno) error {
+	switch e {
+	case 0:
+		return errERROR_EINVAL
+	case errnoERROR_IO_PENDING:
+		return errERROR_IO_PENDING
+	}
+	// TODO: add more here, after collecting data on the common
+	// error values see on Windows. (perhaps when running
+	// all.bat?)
+	return e
+}
+
+var (
+	modshell32 = windows.NewLazySystemDLL("shell32.dll")
+
+	procShellExecuteW = modshell32.NewProc("ShellExecuteW")
+)
+
+func ShellExecute(hwnd int, verb string, file string, args string, cwd string, showCmd int) (err error) {
+	var _p0 *uint16
+	_p0, err = syscall.UTF16PtrFromString(verb)
+	if err != nil {
+		return
+	}
+	var _p1 *uint16
+	_p1, err = syscall.UTF16PtrFromString(file)
+	if err != nil {
+		return
+	}
+	var _p2 *uint16
+	_p2, err = syscall.UTF16PtrFromString(args)
+	if err != nil {
+		return
+	}
+	var _p3 *uint16
+	_p3, err = syscall.UTF16PtrFromString(cwd)
+	if err != nil {
+		return
+	}
+	return _ShellExecute(hwnd, _p0, _p1, _p2, _p3, showCmd)
+}
+
+func _ShellExecute(hwnd int, verb *uint16, file *uint16, args *uint16, cwd *uint16, showCmd int) (err error) {
+	r1, _, e1 := syscall.Syscall6(procShellExecuteW.Addr(), 6, uintptr(hwnd), uintptr(unsafe.Pointer(verb)), uintptr(unsafe.Pointer(file)), uintptr(unsafe.Pointer(args)), uintptr(unsafe.Pointer(cwd)), uintptr(showCmd))
+	if r1 == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}