Add United24

[serhiisp]

United24 described on it's site as "...the main venue for collecting charitable donations in support of Ukraine. Funds will be transferred to the official accounts of the National Bank of Ukraine...".

Also, it is advertised on the site of the Ministry of Digital Transformation.

United24 supports low-friction payment methods, such as PayPal (for medical aid and rebuilding only) and with multiple cryptocurrencies.

To my knowledge, currently the list doesn't contain any option for crypto or PayPal donations to the Government. The NBU offers donations only via credit cards, bank transfers and Google Pay, the rest in the list are non-governmental initiatives.

Therefore, I believe United24 inclusion in the list will be beneficial.

[serhiisp]

Is there something wrong with this PR? Should I rephrase it?

[serhiisp]

Changed wording, removed some, perhaps, "superfluous" information.

[webknjaz]

Ref #139