Update splash screen with new logo and graphics

[alexandrashelenkova]

1. Splash screen Design: https://zpl.io/VDQlky3 https://zpl.io/bAwmkr6

Changes:

• Update logo to a new version
• Update background

2. Loading, syncing, creating wallet screens (goes after this task https://github.com/BeamMW/ios-wallet/issues/505) Design: https://zpl.io/Vq4yZ0Y

Changes:

• Update logo to a new version

[AndreyDyakonov]

Need change background

in masternet:

in design:

[AndreyDyakonov]

Checked