chore: Launch screen on Android is not keeping aspect ratio

[paul-boegelsack]

Summary

Changed the process of generating splash screen files for Android. The assetgen script now generates nine patch files:
https://www.joshmorony.com/creating-a-dynamic-universal-splash-screen-for-capacitor-android/#what-is-a-9-patch-file

Changelog

- Modified assetgen.sh to create splash.9.png files for better splash screen scaling
- Updated .gitignore
- Added launch_splash.xml to use nine patch files

Relevant Issues

Closes #3098

Type of Change

Please select any type below that is applicable to your changes, and delete those that are not.

• Breaking - any change that would cause existing functionality to not work as expected
• Chore - refactoring, build scripts or anything else that isn't user-facing
• Docs - changes to the documentation
• Fix - a change which fixes an issue
• New - a change which implements a new feature
• Update - a change which updates existing functionality

Testing

Platforms

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• Desktop
  • MacOS
  • Linux
  • Windows
• Mobile
  • iOS
  • Android

Instructions

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Checklist

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• I have followed the contribution guidelines for this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or modified tests that prove my changes work as intended
• I have verified that new and existing unit tests pass locally with my changes
• I have verified that my latest changes pass CI workflows for testing and linting
• I have made corresponding changes to the documentation

[amadeu2]

Aspect ratio works perfect on different sicreen sizes, and now looks better as the logo size is homogeneous with the iOS slplash screen. Good work! 💪