UX: Make the save button more pronounced / enable auto-save

[systemofapwne]

When editing package settings, the save button is kind of hidden on the top right so one could easily miss it.
I propose one of the following changes:

• Make it stick out more (e.g. with a frame like the build flags have) when a setting has beenchanged or move below the build flags to be more visible.
• Auto-save whenever build flags are changed

The later one can cause UX issues too: Accidental build-flag deletion then requires and undo-history. I therefore propose to simply make the save button more pronounced.

[Lukas-Heiligenbrunner]

Thanks for the issue.
Yes you are right, thats not great now. I'm not a great UI/UX designer myself so such things are always a pain point for me.

I plan to create an aurcache wide settings page where users can configure some (later most) of the stuff which can be configured with env variables now. And also revamp this package settings page that some of the system wide settings can be overwritten.

So that the settings order is something like this:
Package setting > System wide Setting > ENV variable > Default value

(Maybe system wide settings and env variable order switched, idk tbh. Would also make sense to grey out the settings entries which are configured by env, input appreciated)

Would also be great to be able to configure a custom makepkg.conf and pacman.conf, to configure stuff requested in #283
When i find time I'll add this.