Remove cl dependency in soap-client.el and soap-inspect.el

Remove cl dependency in soap-client.el and soap-inspect.el

* lisp/net/soap-inspect.el: Replace cl library with cl-lib, case
with cl-case, destructuring-bind with cl-destructuring-bind and
loop with cl-loop.

* lisp/net/soap-client.el: Replace cl library with cl-lib,
defstruct with cl-defstruct, assert with cl-assert, case with
cl-case, ecase with cl-ecase, loop with cl-loop and
destructuring-bind with cl-destructuring-bind.

Co-authored-by: Stefan Monnier <monnier@iro.umontreal.ca>