Load configuration data in the registry into a krb5_config_section.
Each registry key corresponds to a krb5_config_section and each
registry value becomes a bound string value.
The set of values contained in the root Heimdal registry key is
treated as if they were defined in the [libdefaults] section.
E.g. the configuration file:
[libdefaults]
foo = bar
[Foo]
x = y
y = {
baz = quux
}
is equivalent to the registry keys:
[HKEY_CURRENT_USER\Software\Heimdal]
"foo"="bar"
[HKEY_CURRENT_USER\Software\Heimdal\Foo]
"x"="y"
[HKEY_CURRENT_USER\Software\Heimdal\Foo\y]
"baz"="quux"
