Change splash screen and Remove "loading..." text during startup

[chrisK00]

Splash Screen

When starting the app a purple color is shown with .NET written in the middle.

Suggestion

• Inside subtrack.maui.csproj the splash screen is defined and you can change the background color there.
• The above works but still displays ".NET". We can add our own svg by creating an SVG using an online editor such as https://editor.method.ac/ and then naming it splash.svg and adding it to the folder inside subtrack.MAUI\Resources\Splash. and have the text "subtrack" in either a white color or light blue like the one used around our cards (might be this hex #2a9fd6)
• The theme should be dark, use a black #000000 background or the grey one that is used for our subscription cards (might be this #222)
• An icon next to the text would be nice but is not a requirement
• The icon here should be the same as the one used for Change app icon  #109

Update

Use the same icon and colors as the app icon added in #165

Loading Text

The "loading" text after the splash screen is just an unnecessary flash as it is barely shown for one second.

Suggestion

• Inside index.html simply only remove the "loading..." text.