Fix wording around "Authenticate in admin"

[SkyLined]

The original wording was unclear to me. After it was explained in the comments for issue 2484, I believe this change best reflects what was originally intended. This should make it easier for users to understand what they are being asked to decide upon.

I only updated the English translation in this edit. In my opinion the de and nl versions are similarly confusing and need updates too. I suspect this also applies to other languages, but I haven't checked.

I can provide these changes for nl once this change is accepted.

[SkyLined]

The "placeholders" (e.g. "Activate the check of password in admin if you plan to access your ioBroker is not in \"Demilitarized Zone\"") still use the old language. I suspect it makes sense to update that as well, or we may get problems with translations into other languages.

Also, I added dots to the end of sentences, which were not there in the original but should have been. I do not know what your policy is for putting punctuation in these placeholders but a quick glance suggests that there is no real policy (e.g. line 64):

64   "Address": "Address",
65   "Address:": "Address",

For consistency, it would make sense to have one and use them in the "placeholders" to avoid missing end-of-sentence dots.