enhance utter_buy_esncard

[alenalin]

consult ESN people on how exactly

[essare-rimaz]

what we should be able to communicate about ESNcard

• price ✅
• where to buy it ✅
• what are the main benefits ✅
• perhaps a link to all ESN CU Prague partners and maybe even ESN International ones too ✅

[essare-rimaz]

done via pr #61