Add support for plugins

[foresterre]

• There is a demo which uses native dylibs, but this doesn't work cross platform and is abi limiting, thus would be a no-go I think

• I've also already spent some time with wasmtime, but got stuck on the (lack of) allowed types and potentially the removal of wasm interfaces (re-adding tracked here: Support for Interface Types in wasmtime API bytecodealliance/wasmtime#677).

• Wasm would be nice, since it would also be programming language independent

• How do you share memory between the wasm sandbox and the process which owns the wasm runtime? (both forth and back)

• How to allow access to third party library from the main process or embed a third party library in the wasm module? e.g. ?I would like to let plugins have access to the image crate through sic_core.

• What should the parsing interface look like (depends on Unified cli-ops & script parser #614)

• What should the apply operation interface look like?

TODO further clarify description