Structure tree should show build limits

[elexis]

Some buildings can only be built N times, for example at most 10 kennels for britons. The limits are stored in a special player.xml template.

This should be loaded by the tech tree and a new function should be added to tooltips.js, so that players can see how often they can build the specific building (or train that specific unit), even if not having started a game.

The existing formatLimitString function can't be reused since it consumes simulation data and the strings aren't what we need here too.

[Imarok]

Move tickets to Misc. UI as "UI & Simulation" got some sub components.