Refactor: Update package structure and implement bottom navigation

This commit refactors the package structure for Gradle convention plugins and introduces bottom navigation to the application.

Key changes:
- Moved Gradle convention plugin files from `dev.adriankuta.partymania` to `dev.adriankuta.flights`.
- Added `TopLevelDestination.kt` to define top-level navigation destinations with icons, titles, and routes.
- Implemented `FlightsBottomBar` Composable in `FlightsApp.kt` to display a `NavigationBar` with items for each `TopLevelDestination`.
- Updated `FlightsNavGraph.kt`:
    - Renamed from `FlightsNavGraph.kt` to `navigation/FlightsNavGraph.kt`.
    - Added `navigateToTopLevelDestination` extension function for `NavController` to handle navigation to top-level destinations with appropriate `NavOptions`.
- Updated `HomeNavigation.kt`:
    - Added `navigateToHome` extension function for `NavController`.
- Added `strings.xml` for `ui:home` module with `home_screen_title`.
- Ensured Kotlin serialization plugin is correctly applied in `app/build.gradle.kts`.

app/src/main/kotlin/dev/adriankuta/flights/navigation/FlightsNavGraph.kt

@@ -0,0 +1,51 @@
+package dev.adriankuta.flights.navigation
+
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.util.trace
+import androidx.navigation.NavController
+import androidx.navigation.NavGraph.Companion.findStartDestination
+import androidx.navigation.NavHostController
+import androidx.navigation.compose.NavHost
+import androidx.navigation.compose.rememberNavController
+import androidx.navigation.navOptions
+import dev.adriankuta.flights.ui.home.navigation.HomeRoute
+import dev.adriankuta.flights.ui.home.navigation.homeScreen
+import dev.adriankuta.flights.ui.home.navigation.navigateToHome
+
+@Composable
+fun FlightsNavGraph(
+    modifier: Modifier = Modifier,
+    navController: NavHostController = rememberNavController(),
+) {
+    NavHost(
+        navController = navController,
+        startDestination = HomeRoute,
+        modifier = modifier,
+    ) {
+        homeScreen()
+    }
+}
+
+fun NavController.navigateToTopLevelDestination(topLevelDestination: TopLevelDestination) {
+    trace("Navigation: ${topLevelDestination.name}") {
+        val topLevelNavOptions = navOptions {
+            // Pop up to the start destination of the graph to
+            // avoid building up a large stack of destinations
+            // on the back stack as users select items
+            popUpTo(graph.findStartDestination().id) {
+                saveState = true
+            }
+            // Avoid multiple copies of the same destination when
+            // reselecting the same item
+            launchSingleTop = true
+            // Restore state when reselecting a previously selected item
+            restoreState = true
+        }
+
+        when (topLevelDestination) {
+            TopLevelDestination.HOME -> navigateToHome(topLevelNavOptions)
+            TopLevelDestination.STATIONS -> navigateToHome(topLevelNavOptions)
+        }
+    }
+}