lib/libwamr: Move to musl and address compiler errors

lib/libwamr: Move to musl and address compiler errors

Move from the `LIBNEWLIBC` and `LIBPTHREAD_EMBEDDED` to `LIBMUSL`.
Changed needed to build lib-wamr were:
* Using the `uk/essentials.h` header for a definition of `offsetof`
* Adding a new `0006` patch file to change `PTHREAD_MUTEX_RECURSIVE_NP` into
`PTHREAD_MUTEX_RECURSIVE` as the former on isn't defined
* Change the `0005` patch file to use modern working unikraft initrd loading
code so it can load the `.wasm` files

Signed-off-by: Robert Klink <roberthklink@gmail.com>
Signed-off-by: Ricardo Mohamedhoesein <rmohamedhoesein3@gmail.com>
Co-authored-by: Ricardo Mohamedhoesein <rmohamedhoesein3@gmail.com>
Reviewed-by: Eduard Vintilă <eduard.vintila47@gmail.com>
Reviewed-by: Stefan Jumarea <stefanjumarea02@gmail.com>
Approved-by: Razvan Deaconescu <razvand@unikraft.io>
Tested-by: Unikraft CI <monkey@unikraft.io>
GitHub-Closes: #8