UI: Please change memory setting in flex compute offering from MiB to GiB

### The required feature described as a wish

As a user, I'd like to be able to set the memory size of my instances in GiB without having to calculate the correct MiB value.
Entering values in MiB tends to lead to entering round numbers of 1,000. This then results in odd GiB values.
If a VM with less than 1 GiB is ever actually needed, you can enter 0.5 GiB, for example.
However, this use case is likely to occur much less frequently than higher GiB values.

Maybe it could include a drop-down menu next to the value that uses GiB as the default but also allows MiB to be selected. But I think GiB is the most helpful for most people.

Comienza localizando la UI de la oferta de flex compute y el campo de memoria que actualmente acepta valores en MiB; después, revisa las pruebas de UI cercanas. Se considera terminado cuando los usuarios pueden introducir memoria en GiB de forma predeterminada, incluidos valores fraccionarios como 0.5, con la alternativa solicitada en MiB si el diseño existente admite un selector de unidades.

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