feat: display application period closed

[LiviaValenti]

Closes #40

Summary of changes

• Add axios-call that retrieves boolean value from backend (/applications/period/active) and assigns this to a state
• Add a Box-component that notifies the user of the form that the period is now closed - the form doesn't load if the period is closed
• Add styling to Box-component
• Add Loader-component and add some styling

[LiviaValenti]

Currently it works as a minimal solution, which is great 🚀

There are some minor improvements (that require some frontend date-logic) that I would like to see implemented. Regarding the visual representation I am not feeling too inspired at the moment. Perhaps @HenrikVL has some ideas?

[LiviaValenti]

I would like this to inform the user a bit more:

• If the admission period is underway: "Frist for innsending av søknad DD-MM-YYYY 23.59"
• If the admission period has passed: "Opptaket var fra DD-MM-YYYY til DD-MM-YYYY."
• If the admission period is in the future: "Opptaket er fra DD-MM-YYYY til DD-MM-YYYY."
• If the admission period does not exist in db: "Opptaksperioden er ikke satt enda."

Not all cases are required. I find the first one the most important.

@Xtrah probably has some opinions on this 👂🏼

[Xtrah]

I think the first one is definitely the most important ℹ️ It can even be simpler - "Søknadsfrist DD-MM-YYYY 23:59"

I don't think we need the other information. We could edit the general closedText to something like this instead:

NTNUI Admin har for tiden ingen opptak
Vi har vanligvis opptak på starten av hvert semester.
Leter du etter opptak til en NTNUI gruppe eller lag? Sjekk gruppens egen nettside!

[LiviaValenti]

@supapesh perhaps you could take a look at implementing this? I believe the suggestion Mats gave is fitting. ✨

[supapesh]

Mats' suggestions have been implemented (thanks to Livia for the help<3)

The hyperlink on the "gruppens" redirects to medlem.ntnui.no.

[HenrikVL]

Great job! I approve 🙌