Don't show the main menu when returning to the server browser.

Fixes #4902.
Add IMove.MoveIntoWorld and IMove.VisualMove.
Use MoveIntoWorld for production.
Use MoveIntoWorld for Enter activities.
Use MoveIntoWorld for transports. Fixes #4758.
Remove RenderLandingCraft dependency on Mobile.
Remove RenderInfantry dependency on Mobile.
Fix start-game UI acceleration.
Merge pull request #4909 from reaperrr/remap-engineer

Remap fixes for RA Engineer and SAM site
Closes #4862
Closes #4876
Merge pull request #4910 from pchote/menu-fix

Fixes #4902
Merge pull request #4915 from pchote/ui-tick-fixup

Fix start-game UI acceleration.
Fix UpgradeRules not upgrading maps.
Remove duplication between Immobile and Mine.
Allow support powers to define a poster image for beacons.
Add posters for TD airstrike and nuke.
Remove incorrect padding from the top of the mod browser list.
Make the TD menu button positions consistent. Fixes #4735.
Add settings tab to TD lobby. Partially fixes #4770.
Merge pull request #4923 from pchote/td-ui-consistency

TD menu layout improvements.
Merge pull request #4921 from pchote/mod-browser-fix

Remove incorrect padding from the top of the mod browser list.