added support for altcha translations

[xgimp]

I Added support for Altcha translations. Should resolve issue #22

I added ALTCHA_INCLUDE_TRANSLATIONS settings that is False by default. My thinking was that by default, you want to include as little javascript as posible.

Also if user provides his own ALTCHA_JS_URL he probably bundles translations he needs.

[tdruez]

Hi @xgimp, thanks for reporting and looking into this.
Instead of a new setting, should we include the extra JS based on the presence of language argument when declaring the field, as in AltchaField(language="cs")?

[xgimp]

Hello,

I was thinking, that in case when user provides his own ALTCHA_JS_URL with bundled or customized translations it could be accidently overrided or included twice, if we just load the translations based on the language argument.

for example:

ALTCHA_JS_URL = "myBundleWithCsLangIncluded.js"

class SomeForm(forms.Form):
    captcha_field = AltchaField(
        language="cs"
    )

<script async defer src="myBundleWithCsLangIncluded.js" type="module"></script>
<script async defer src="<'cs' languge included by us based on language parameter>" type="module"></script>
<!-- in this case the language is included twice -->
<altcha-widget>

So that is why I implemented the switch :-).