Refactor: Update dependencies and Gradle configuration

This commit updates various dependencies and reconfigures Gradle settings to newer versions and standards.

Specific changes include:

-   Updated Android Gradle Plugin to 8.6.1
-   Updated Kotlin to 2.1.20
-   Updated Compose Compiler to 1.5.15
-   Updated Compose BOM to 2025.04.01
-   Updated Hilt to 2.54
-   Updated KSP to 2.1.20-2.0.0
-   Updated other dependencies like Navigation, Core-Ktx, Lifecycle, Activity Compose, Room, Paging, Coil, Serialization Json
-   Migrated to Java 21
-   Applied Compose plugin
- Updated target and compile SDK to 35
- updated jvm target to Java 21

app/build.gradle.kts

@@ -8,7 +8,7 @@ android {
 
     defaultConfig {
         applicationId = "dev.adriankuta.pixabay"
-        targetSdk = 34
+        targetSdk = 35
         versionCode = 1
         versionName = "1.0"
     }
@@ -23,7 +23,7 @@ android {
         }
     }
     kotlinOptions {
-        jvmTarget = JavaVersion.VERSION_17.toString()
+        jvmTarget = JavaVersion.VERSION_21.toString()
     }
     buildFeatures {
         buildConfig = true