dependencies: switch from Wasmer to Wasmtime (#3349)

* Remove ForeignFunctionEnv wrapper around PluginEnv

This will enable PluginEnv to be the Store context when migrating to
Wasmtime.

* Pass PluginEnv by value to load_plugin_instance

This will allow removing the Clone impl from PluginEnv when migrating to
Wasmtime as required by the missing Clone impl on Wasmtime's WasiCtx.

* Avoid passing a Store around when an Engine is enough

* Pass PluginEnv to the wasi read/write functions

Wasmtime requires storing the read/write end of the pipe outside of the
WasiCtx. Passing PluginEnv to these functions allows storing them in the
PluginEnv.

* Migrate to Wasmtime

* Switch from wasi-common to wasmtime-wasi

* Reduce verbosity of wasmtime_wasi logs

* Increase startup delay

To wait for all plugins to be compiled.

* Disable some wasmtime features

* Update to Wasmtime 21.0.1

CONTRIBUTING.md

@@ -92,7 +92,7 @@ Note that the output is truncated at 100KB. This can be adjusted for the purpose
 When running Zellij with the `--debug` flag, Zellij will dump a copy of all bytes received over the pty for each pane in: `/$temp_dir/zellij-<UID>/zellij-log/zellij-<pane_id>.log`. These might be useful when troubleshooting terminal issues.
 
 ## Testing plugins
-Zellij allows the use of the [Singlepass](https://crates.io/crates/wasmer-compiler-singlepass) compiler for wasmer. This can enable great gains in compilation time of plugins in detriment of stability, notably on Arm64 architectures.
+Zellij allows the use of the singlepass [Winch](https://crates.io/crates/wasmtime-winch) compiler for wasmtime. This can enable great gains in compilation time of plugins at the cost of slower execution and less supported architectures.
 
 To enable the singlepass compiler, use the `singlepass` flag. E.g.:
 ```sh
@@ -113,7 +113,7 @@ If you are new contributor to `Zellij` going through
 [Discord server][discord-invite-link], we would be happy to help finding
 something interesting to work on and guide through.
 
-[discord-invite-link]: https://discord.gg/feHDHahHCz 
+[discord-invite-link]: https://discord.gg/feHDHahHCz
 [good-first-issue]: https://github.com/zellij-org/zellij/labels/good%20first%20issue