Fix Issues when building with XCode 13

[eddielement]

When building the app in XCode 13, there are several UI issues.

• Transparent splash screen

• Transparent navigation bar till I scroll up the screen

The video with 1 and 2: https://user-images.githubusercontent.com/7028613/182032101-e62f3157-217c-4e1d-a312-3a583481197f.mov

• Untappable tip textfield and +Add another button.

[pankova]

I could help with the issue or with another task, if plan to do it.

[eddielement]

Your help would be greatly appreciated! I did some research that might be helpful:

• To get the simulator working on M1 Macs, go to Build Settings -> All -> Excluded Architectures -> add 'arm64' to iOS Simulator
• The navigation bar thing seems to be due to an outdated bar. In the storyboard, I can highlight the navigation bar and select a type and that makes it opaque again, but then it just needs to be colored blue.

[pankova]

As part of this task, minimum iOS version can be bumped to iOS 13, if you don't mind.

[pankova]

Also I've noticed, there is a problem with the tab bar shadow until scrolling down. I'll try to fix it in the PR as a part of Xcode 13 issues.

[eddielement]

As part of this task, minimum iOS version can be bumped to iOS 13, if you don't mind.

Sounds good! :)