Add Java and C code of SQLite JDBC

mailbox-android/.gitignore

mailbox-android/build.gradle

...ava/org/briarproject/mailbox/core/DatabaseCreationTest.kt

mailbox-android/src/main/cpp/CMakeLists.txt

mailbox-android/src/main/cpp/NativeDB.c

mailbox-android/src/main/cpp/NativeDB.h

mailbox-android/src/main/cpp/sqlite3.h

mailbox-android/src/main/cpp/sqlite3ext.h

mailbox-android/src/main/cpp/sqlite3mc.def

mailbox-android/src/main/cpp/sqlite3mc_amalgamation.c

mailbox-android/src/main/cpp/sqlite3mc_amalgamation.h

mailbox-android/src/main/java/org/sqlite/BusyHandler.java

...box-android/src/main/java/org/sqlite/ExtendedCommand.java

mailbox-android/src/main/java/org/sqlite/Function.java

mailbox-android/src/main/java/org/sqlite/JDBC.java

...box-android/src/main/java/org/sqlite/ProgressHandler.java

...ndroid/src/main/java/org/sqlite/SQLiteCommitListener.java

mailbox-android/src/main/java/org/sqlite/SQLiteConfig.java

...ox-android/src/main/java/org/sqlite/SQLiteConnection.java

...roid/src/main/java/org/sqlite/SQLiteConnectionConfig.java