feat: add support for loading dotenv files

[Lehoczky]

Closes #56

This PR adds a new option to the CLI, --env, which specifies which env file to load before a command is executed.

[cyyynthia]

I'm unsure how to feel about that. I'm aware we can't fetch env variables be fetched before because we need to get --env, however doing manually the env checks does duplicate the places where it needs to be handled and is prone to desync...

Iterating over the list of available options stored in program is probably better

[Lehoczky]

I can do a followup refactoring PR to handle loading the configuration in one place, potentially with a schema library, like zod, which would further simplify things.

The reason I did not iterate here, because different options need different parsing function, like the TOLGEE_PROJECT_ID needs the parseProjectId().

[cyyynthia]

Isn't the parse function already stored and accessible via the list of available options?

[Lehoczky]

Would you be able to show me a code snippet on how we could improve this function? I might just be slow today, but it would help me for sure.

[cyyynthia]

It's possible to get the list of options that can be specified on a given command using the options field; considering this I wonder if it's not possible to use this (along with parent since commands are structured in a tree-like structure) to get all the options that can be specified, and check if the option can use an env variable, if so use its parser and its name() to populate the command options - see this

[Lehoczky]

I haven't find a way to iterate over the options and set the env variables that way. It is not possible to get whether an option can use an env variable.

[cyyynthia]

Hello, sorry for the late reply, I unfortunately got sick 🤧

I was able to iterate over all the options using this snippet:

function processCommand (command: Command) {
  for (const option of command.options) {
    console.log(option.attributeName(), option.envVar)
  }

  if (command.parent) {
    processCommand(command.parent)
  }
}