Fixed Masked SettingType

[ashnove]

This closes https://github.com/RocketChat/Rocket.Chat.Apps-engine/issues/238

The fix/hack I've added is to append a PASSWORD attribute to the SettingType enum and used it in the provideSetting configuration.

[CLAassistant]

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2 out of 3 committers have signed the CLA.

:white_check_mark: ashnove
:white_check_mark: d-gubert
:x: casalsgh
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[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
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[graywolf336]

Is this a duplicate of #577?

[ashnove]

Is this a duplicate of #577?

Seems like it

[pierre-lehnen-rc]

Just the first part - My PR only adds password to the list, but doesn't change any setting to use it.