Handle PATs UI loading states

[easyCZ]

When we're loading PATs (either List, Get, Create etc), add a loading screen transition.

[jeanp413]

@gtsiolis is there a mockup for this?

[gtsiolis]

@jeanp413 No, but I'm not sure how much needed is this for this iteration. The dashboard is running into this interaction issue also when loading other pages like variables, etc. @easyCZ Is this something we'd like to work on now?

If yes, a good MVC solution for this could be to re-use the same loading pattern with the spinner we use for loading branches and prebuilds lists, see screenshots below.

Branches ✔️	Prebuilds ✔️	Tokens 🚧

[easyCZ]

@gtsiolis Yes, indeed. It's scheduled in the current iteration.

And exactly as @gtsiolis suggested, nothing new or special is needed here, just showing something while the requests are pending. That goes for all the actions - loading the list, creating a token, etc..

[mustard-mh]

Added component Loader.tsx with SpinnerLoader and SpinnerOverlayLoader

SpinnerLoader	SpinnerOverlayLoader