Allow unsupported languages for api > since llm probably supports them

Instead of giving

{
	"error": "tk is not supported"
}

for unsupported languages, what about just allowing them when using the api? Its easier than expanding the language file for every language, and the llm probably supports them :)

example query for Turkmen:

{
		"q": "good morning sir",
		"source": "en",
		"target": "tk",
		"format": "text",
		"api_key": ""
	}

I did try adding to the languages file, rebuilding, and running, and that works no problem... but it would be cool not to need to modify the source when pulling the latest :)

Its pretty cool, thanks!

Start by tracing the API validation that returns the unsupported-language error and inspect the languages file, which the issue mentions modifying. Verify the Turkmen example request and confirm that unsupported targets can be accepted without changing the source language list.