Add BackgroundWrapper component

[katomm]

• Add BackgroundWrapper component to use the ada logo in a background. See https://cardano.org/docs/components/background-wrapper/ for details.
• Added to showcase page as an example.

[gufmar]

₳ to the
back side of the
moon

[rphair]

nice feature 😎 FYI my local build gets these warnings:

[WARNING] {"file":"assets/css/styles.e1c6c343.css","message":"assets/css/styles.e1c6c343.css from Css Minimizer plugin\nUnexpected '}' at assets/css/styles.e1c6c343.css:25:58492.","compilerPath":"client"}
[WARNING] {"file":"assets/css/styles.e1c6c343.css","message":"assets/css/styles.e1c6c343.css from Css Minimizer plugin\nUnexpected '}' at assets/css/styles.e1c6c343.css:25:58650.","compilerPath":"client"}
[WARNING] {"file":"assets/css/styles.e1c6c343.css","message":"assets/css/styles.e1c6c343.css from Css Minimizer plugin\nUnexpected '}' at assets/css/styles.e1c6c343.css:25:58949.","compilerPath":"client"}
[WARNING] {"file":"assets/css/styles.e1c6c343.css","message":"assets/css/styles.e1c6c343.css from Css Minimizer plugin\nUnexpected '}' at assets/css/styles.e1c6c343.css:25:59179.","compilerPath":"client"}
[WARNING] {"file":"assets/css/styles.e1c6c343.css","message":"assets/css/styles.e1c6c343.css from Css Minimizer plugin\nInvalid property name '.backgroundSolidGrey_rFbg{background-color' at assets/css/styles.e1c6c343.css:25:58441. Ignoring.","compilerPath":"client"}
[WARNING] {"file":"assets/css/styles.e1c6c343.css","message":"assets/css/styles.e1c6c343.css from Css Minimizer plugin\nInvalid property name '.backgroundSolidBlue_wL82{background-color' at assets/css/styles.e1c6c343.css:25:58599. Ignoring.","compilerPath":"client"}
[WARNING] {"file":"assets/css/styles.e1c6c343.css","message":"assets/css/styles.e1c6c343.css from Css Minimizer plugin\nInvalid property name '.backgroundGradientDark__tON{background-image' at assets/css/styles.e1c6c343.css:25:58863. Ignoring.","compilerPath":"client"}
[WARNING] {"file":"assets/css/styles.e1c6c343.css","message":"assets/css/styles.e1c6c343.css from Css Minimizer plugin\nInvalid property name '.backgroundGradientLight_VZGR{background-image' at assets/css/styles.e1c6c343.css:25:59092. Ignoring.","compilerPath":"client"}