options: simplify option parsing/setting machinery

options: simplify option parsing/setting machinery

Each option type had three separate operations to copy option values
between memory locations: copy between general memory locations
("copy"), copy from general memory to active configuration of the
program ("set"), and in the other direction ("save"). No normal option
depends on this distinction any more. Change everything to define and
use a single "copy" operation only. Change the special options
"include" and "profile", which depended on hacky option types, to be
special-cased directly in option parsing instead. Remove the now
unused option types m_option_type_func and m_option_type_func_param.