Mateusz

[Matimateokol]

Hi guys, I have made the following changes to the project:

• Updated the build tool (Gradle) version to 7.0.1 and Kotlin to 1.5.21 .
• Added background image, ic_backarrow image and leading theme colors.
• Defined some of leading theme colors in colors.xml file.
• Created round_btn and customizable ToolBar.
• Imported "roboto" font from Google fonts.
• Created transition between StartActivity and SignIn.

Let me know if the changes have caused any bugs or other issues.

[Matimateokol]

Seems ok to me, therefore I am merging pull request.