WASM Support

[commial]

Supporting a WASM version of MLA would be nice.
For instance, it would allow the support of:

• in-the-browser opening of compressed and encrypted HTML reports
• a platform agnostic GUI (in the browser)

Targeting WASM in Rust has some requirements. This issue is made to track them:

• List actual requirements

---

For now, compiling to WASM WASI is working:

# Compile to WASI
$ cd mlar
$ cargo build --target=wasm32-wasi --release

# Get the resulting `wasm` file
$ cd /workspace/MLA/target/wasm32-wasi/release/
$ file mlar.wasm 
mlar.wasm: WebAssembly (wasm) binary module version 0x1 (MVP)

# Execute it using `wasmtime` (file access is sandboxed)
$ wasmtime  mlar.wasm list -i /workspaces/MLA/samples/archive_v1.mla -k /workspaces/MLA/samples/test_x25519_archive_v1.pem
...
[ERROR]
...
failed to find a pre-opened file descriptor
...

# Allow accesses to the source directory
$ wasmtime --dir /workspaces/MLA/samples/  mlar.wasm list -i /workspaces/MLA/samples/archive_v1.mla -k /workspaces/MLA/samples/test_x25519_archive_v1.pem | head
big
file_0
file_1
file_10
file_100
file_101
file_102
...