feat: a couple of ideas

[peterpeterparker]

Hi Jorge,

I had a quick look at the "party service" and here's a couple of spontaneous ideas :

• createParty and deleteParty had no return types specified
• promise of navigateByUrl was not handled
• in party.page.ts I would init the observable variable only once so that you don't init a stream (even if empty) without closing it before assigning it again to the effective stream which should be displayed
• in getPartyList and getPartyDetail just a quick draft to leverage rxjs
• I also quickly added prettier and only formatted the code I modified (might run a npx prettier --write . afterwards if you think it's a good idea)

Hope it helps, cool repo! Starred ⭐️

P.S.: Note I did not test my code at all, therefore good possible it does not work. This PR has no other goal than sharing some spontaneous ideas.