Beautify the login window suggestion

[chuxinyuan]

Thank you very much for developing this package, which perfectly solves the user and role rights issues. Here are a few half-baked suggestions I'd like you to consider：

1. Can the login window be placed in the center of the display? Otherwise, the user needs to look up.
2. User name and password are usually not very long, can you make the input box a little shorter?
3. Increase the height of the entire login window, similar to RStudio Server.
4. Added the args to customize the background color of the login window.

Thanks.

[chuxinyuan]

@PaulC91 It doesn't seem to be a very important question, so I'm going to turn it off.

[PaulC91]

Hey, thanks for these suggestions.

I plan to include more UI customisation options in a future release but I don't have time to work on it right now.

If you need these options now I suggest you make your own fork of the package and edit the code in the loginUI function to suit your needs.

Thanks

[chuxinyuan]

@PaulC91 I have enough patience. Ha ha ha……