Plug GSupplicant reference leak

See merge request !6

[gsupplicant] Clear only blobs that are being set. Contributes to JB#45980

See merge request !5

JB#44692: Add support for wpa_supplicant blobs of inlined cert data

See merge request !4

  gsupplicant_bss_remove_all_handlers
  gsupplicant_interface_remove_all_handlers
  gsupplicant_network_remove_all_handlers
  gsupplicant_remove_all_handlers

Compatibility with glib 2.56

See merge request !3

Handle "notify" instead of "g-properties-changed". It's advertised
by glib docs as the right way of doing it.

If the stubs are generated by gdbus-codegen < 2.56 then strv getters
return shallow copy, i.e. the return result should be released with
g_free(), but the individual strings must not be modified. Luckily,
this can be determined at compile time.

See https://bugzilla.gnome.org/show_bug.cgi?id=770335

Don't rely on gutil_types.h to pull it in.

Maintain the list of connected stations

See merge request !2

This adds 'stations' field to GSupplicantInterface

This is primarily to make gsupplicant_util.h gio-free

Treat SSIDs consisting of all zeros as empty

See merge request !1

Not much can be unit-tested though

Avoid using g_variant_get_data_as_bytes and g_hash_table_get_keys_as_array