Unoccupied outpost stands in darkness

[Langbart]

Zero Vision originates from an unoccupied outpost in my own home territory. Shouldn't it at least have a vision, such as a storehouse? (Image below for more clarity)

[wraitii]

Hmm, this actually _is_ a bug because it's supposed to have 4 Vision.

I fix this in ​Phab:D3054

We could give it something like 8 Vision to make sure it's at least selectable [edit: it had 4 and was in fact selectable, but looks odd).

I'm not sure if we need to fix it for A24 but I'm moving the ticket back to get discussion, because I fear we might get many reports on this

[wraitii]

In 24779:

Increase outpost base vision to 10

Outposts have a vision range of 4. This however does not always reveal FoW around them, which looks rather odd (see D3054).
Give them 10 vision so that it's obvious they are working, and clarify the tooltip that garrisoning is needed to make them helpeful.

Fixes #5974

Differential Revision: ​https://code.wildfiregames.com/D3464

[Langbart]

Files should be hosted by Trac, otherwise they will not be accessible when the original provider (​https://imgbb.com) dies. Changed the link and will upload the image to Trac.