Integrating Google, Apple, Github Authentication

[mirzemehdi]

Implemented Google, Apple, Github authentication integrations using Firebase
Developed new kmpauth-uihelper module that contains Google and Apple Sign-In Buttons
Updated sample code.
Updated Documentation.

Sample Usage

@Composable
fun AuthUiHelperButtonsAndFirebaseAuth(
    modifier: Modifier = Modifier,
    onFirebaseResult: (Result<FirebaseUser?>) -> Unit,
) {
    Column(modifier = modifier,verticalArrangement = Arrangement.spacedBy(10.dp)) {

        //Google Sign-In Button and authentication with Firebase
        GoogleButtonUiContainerFirebase(onResult = onFirebaseResult) {
            GoogleSignInButton(modifier = Modifier.fillMaxWidth()) { this.onClick() }
        }

        //Apple Sign-In Button and authentication with Firebase
        AppleButtonUiContainer(onResult = onFirebaseResult) {
            AppleSignInButton(modifier = Modifier.fillMaxWidth()) { this.onClick() }
        }

        //Github Sign-In with Custom Button and authentication with Firebase
        GithubButtonUiContainer(onResult = onFirebaseResult) {
            Button(onClick = { this.onClick() }) { Text("Github Sign-In (Custom Design)") }
        }

    }
}