Xib removed. Crashes fixed.

In this release:

• Xib files completely removed. Only code UI 🔥
• Stevia updated for SPM and cocoapods.
• Fixed crash when tapping flash button with front camera. Thx @AdamBCo
• Square button is hiding with multiple selection mode.
• Moved back to Stevia 4.8.0 for SPM and SteviaLayout 4.7.3 for cocoapods. Need it to have a common namespace for Stevia methods to support the both - cocopods and spm.

Thx:

• @AlekseyPakAA for #706
• @hhariprsd for #705

Full Changelog: 5.0.0...5.1.0