feat: run workers in installed language runtimes

[Angelmmiguel]

This PR configures wws to run new workers based on the installed language runtimes. Now, wws loads the configuration to detect if there're new file extensions available. Then, it will initiate the runtime for files with those extensions so they can receive requests.

I had to update the different structs that initiates the workers to ensure the Config is only load once.

Regarding how the runtimes are configured, the worker ExternalRuntime is in charge of preparing the source code when wws starts. Then, it will configure the WASI context on every request. All the required configuration is in the Runtime metadata (see #65)

Example

$ ls
worker.rb  wws

$ wws .
⚙️  Loading routes from: .
🗺  Detected routes:
🚀 Start serving requests at http://127.0.0.1:8080

$ wws runtimes install ruby 3.2.0
⚙️  Fetching data from the repository...
🚀 Installing the runtime...
✅ Done

$ wws . 
⚙️  Loading routes from: .
🗺  Detected routes:
    - http://127.0.0.1:8080/worker
      => ./worker.rb (name: default)
🚀 Start serving requests at http://127.0.0.1:8080

It closes #80

[assambar]

LGTM! Learned a lot while reading this!