Add new basic Pop theme

[mmstick]

Provides a simple theme which focuses primarily on the decryption screen.

• Features a blinking cursor within the password entry
• Places the password prompt text beneath the entry, centered.
• Entry has a return key to signal for the user to press enter

[jackpot51]

This looks really good. I am testing it on my NVIDIA laptop

[mmstick]

Just added the return key arrow to the entry, and it should be ready now.

[brs17]

@mmstick @jackpot51

No Pop!_OS logo on the wilp14 on intel graphics

[jackpot51]

We removed the Pop logo, for simplicity

[brs17]

ah, ok.

[aden-young]

This looks really slick! Will it be rolled out automatically? My computer still has no theme during the boot / decryption process.

[mmstick]

@aden-young This has been shipping since the PR was merged. You should be seeing it (I've been seeing it on all the systems I've installed Pop on).