ui: drop the clipboard/paste JSON buttons from Cards and custom files (v2.5.1)

- Cards and Custom files now expose only Export to file (JSON download) and
  Import from file; the Export-as-JSON / Paste & import / Import-JSON-from-
  clipboard buttons and their paste textareas are gone
- import feedback moves to a transient status line (new ioStatus helper);
  cardsImport/pysimCustomImport no longer read the clipboard
- Network simulation parameters: note under the operator form listing the
  scenarios that use the MCC/MNC (EPS/2G attach and SMS received write real
  LAI/RAI/TAI; cold boot, service lost, limited service and roaming denied
  write dummy files keeping the PLMN; churn/CB/AUTHENTICATE do not use it)
- i18n: removed-button entries dropped, note added EN/RU; help EN/RU updated
- guard tests for the button set and the note; SW cache simple-v196

pysim_simple_server/server.py

@@ -24,7 +24,7 @@ from osmocom.construct import GsmOrUcs2Adapter
 from osmocom.tlv import BER_TLV_IE
 
 
-VERSION = '2.5.0'
+VERSION = '2.5.1'
 
 MAX_ENVELOPE_SEGMENTS = 5  # max SMS segments for outgoing C-APDU in ENVELOPE