feat: allow mounting folders in workers

[Angelmmiguel]

Introduce a new feature to mount arbitrary folders in a specific workers. It allows developers to provide assets and libraries to the workers as they need. To mount a folder, you only need to add a new configuration parameter in the worker config:

version = "1"

[[folders]]
from = "./_assets"
to = "/src/assets"

Note this configuration is defined at worker level. Every worker can define their own sets of required folders.

Other changes

• Move the worker configuration from the Route struct to the Worker
• Remove the name config property from the CLI output. It's not providing any meaningful information
• Provide always a default configuration to avoid dealing with Option
• Add a new python-mount example
• Ignore files and folders that starts with _. Those will be the folders that will be mounted later on

It closes #53