feat: show info when hovering claims in JWT Encoder

[mikyll]

Feature Request

The old UI allowed to see the equivalent date time of "iat", "exp" and "nbf" claims (and also info about standard claims) when hovering them with cursor. Currently only the JWT Decoder supports that, but I think it's most useful when editing them. Can you add this feature to the JWT Encoder as well?

Context

JWT Encoder:

JWT Decoder: