Provide a "reviewed" checkbox in the in-context editor plugin

[jdimeo]

For my use case, marking a translation as reviewed "releases" the translation for the next step (until then, it will be modified by the API since it's the combination of two other independent translations and the user reviews it and makes final edits). It would be great if there was an option to mark the translation as reviewed when editing in-context so that the user doesn't have to go to the system, find the key, mark reviewed manually (or be confused as to why the API keeps changing their translation since it wasn't "locked" in our use case)