Show StageInfo window in OAB/VAB

[Falki-git]

This PR brings StageInfo to OAB/VAB

Release change log:

• add StageInfo window to VAB
• window positions and states are now automatically saved on scene changes
• windows no longer persist on scene changes (Flight <-> Space Center <-> VAB)
• windows automatically open when entering Flight and VAB scenes if user didn't close them previously

Dev change log:

• Add StageInfoOAB window for OAB/VAB
• Add MicroEntries for StageInfo in OAB
• Add OAB app button for StageInfoOAB window
• Add 3 message subscriptions:
  • VesselDeltaVCalculationMessage: used for StageInfoOAB window updates (lower impact than Update())
  • GameStateEnteredMessage: used for automatically setting window visibility and loading layout states
  • GameStateLeftMessage: used for automatically setting window visibility and saving layout states
• Layout states are now automatically saved and loaded on scene (gamestate) changes
• MainGui window (Flight) and StageInfoOAB window (OAB/Editor) are now automatically opened on entering a scene if user didn't close them previously
• MainGui window now automatically hides when not in Flight
• Prettify StageInfoOAB
• Remove empty stages from window
• Add CelestialBodies select
• Adjust TWR depending on CelestialBody
• Use Vacuum TWR for SLT for Bodies without Atmosphere
• Adjust design of the body selection button
• Add descriptions for all new entries
• Annotate properly

[Falki-git]

Progress:

[Falki-git]

@Micrologist , ready to merge this.