Fix splashscreen not showing <= API 30

Task/Issue URL: https://app.asana.com/0/1207908166761516/1206826738295232/f

Description

The splashscreen was not showing on devices on devices <= API 30.

To fix this I used the spashscreen-compat library and removed the need for dedicated splashscreen styles on API 31+ as the compat library will take of that for us.

The splashscreen is very quick on a warm start on <= API 30 (see the demos) but I don’t think it’s worth adding any kind of artificial delay to show it for a longer period.

Steps to test this PR

If you have a device that’s <= API 31 to test then please do! Unfortunately I do not have a device on hand at that API level.

[x] Pick a device <= API 31 (preferably not an emulator)
[x] Install the app
[x] Run the app
[x] Check that the splashscreen shows
[x] Pick a device > API 30 (preferably not an emulator)
[x] Install the app
[x] Run the app
[x] Ensure the splashscreen is still present

UI changes

API 26 before shown as a demo for all devices < 30

I’ve provided some before videos on actual devices on >= API 30

Before	After

duckduckgo / Android