Adding new structs and functions

1. Create C safe Rust structs and related functions using safer-ffi

2. Test generated library and bdk_ffi.h file with c language tests in cc/bdk_ffi_test.c

3. Use build.sh and test.sh to build c test program and verify functionality and memory de-allocation via valgrind

4. Update the kotlin native interface LibJna.kt in the bdk-kotlin jvm module to match bdk_ffi.h

5. Create kotlin wrapper classes and interfaces as needed

6. Add tests to bdk-kotlin test-fixtures module

7. Use build.sh and test.sh to build and test bdk-kotlin jvm and android modules