Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

The plan is to migrate the CI to not need any passwords. This constant
can be used to give a dummy password.

- especially for plmn_list, will allow to be followed by an MCC/MNC in a
  single line
- tightens regexes to match replacements more accurately, e.g., "val =
  key" (instead of just searching for "key)
- no special rule for SD, which matches SD values (and not the SD
  field). However, currently it is not possible to specify multiple SDs
  (multiple SSTs was already not possible)

the following:

         if (cur_wait_list == entity->wait_end)
           end_wait_list = prev_wait_list;

was done after cur_wait_list is updated to its new value, but the old value
has to be used in this test. So end_wait_list was not set properly.

This was leading to random crashes later on because then entity->wait_list
was NULL but entity->wait_end was not (because of the bug fixed by this
commit).

The new value for cur_wait_list is also now set using prev_wait_list->next
just before the goto, as done in other places in the code.

Also "cur" was removed, for it has no purpose and makes the code harder
to understand.

The loop passes over all keys. For plmn_list, there are subentries mcc,
mnc, mnc_length. The plmn_list if block assumes that the key is a dict,
which was not checked for, leading to a type error.

Following changes included:
- SD is optional: when value is 0xffffff or not present in config
  (previously: needed to be set to 0)
- Checks SSTs in range [0,255]
- Checks SDs in range [0,0xffffff]
- Correct typo SST defines