Upgrade Swift version & Refactor

[emrcftci]

Description

• Fix indentations

• Change guard to if let;

  • guard is an early return statement so we should use if let in prepare()

• Upgrade Swift version to Swift 5.0

• Enable Base Internationalization

Motivation and Context

• We'll solve warnings,

• We'll fix indentations,

• We'll have a upgraded Swift version

after this pull-request merge.

What kind of change does this PR introduce?

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] File changes for improvement
• [ ] New feature (non-breaking change which adds functionality)
• [x] This change requires a documentation update

[emrcftci]

Thanks for the project! Could you please check this pr? 🚀 @AppliKey