chore: reduce jar file size and unsupport sqlite/postgresql/mysql

build.gradle.kts

@@ -38,9 +38,7 @@ dependencies {
     implementation(libs.exposed.core)
     implementation(libs.exposed.jdbc)
     implementation(libs.exposed.dao)
-    implementation(libs.sqlite.jdbc)
-    implementation(libs.mysql.jdbc)
-    implementation(libs.postgressql.jdbc)
+    implementation(libs.h2.jdbc)
     implementation(libs.motd.pinger)
     implementation(libs.animated.gif.lib)
     implementation(libs.simple.java.mail)