New action: Hide and Replace With Tabs

[aecreations]

(Original Bugzilla ID: 25181)

This enhancement is to the Hide and Replace action that was introduced in
version 1.5. Add the ability to replace the user's browsing session with
multiple tabs, each displaying a URL that is specified in extension
preferences. Users should be able to specify 1 or more URLs to open, and add
more as desired.

[aecreations]

This enhancement has been dropped from version 2.0.