Add a flight mode to the game

[stavbsh]

Please add a jetpack button above the player username area as the screenshot below:

Below are the flight menu modes:

1. Default: the players starts the game with 5 minutes of flight time.
2. Hover: the player can enter flight mode by clicking the jetpack button or by pressing the F key.
3. Active: during the flight the height and speed parameters are displayed.
4. Inactive: after the players have reached their flight time limit.

Flight mode info:

• Players can enter flight mode as long as they didn't reach their flight time limit.
  • The flight starts at a default height with no speed.
  • During the flight the player's 3D model should be displayed in an angle (the model slightly looking down).
  • Flight movement and walking have the same operation keys (W - move forward, W + shift - move forward fast)
  • The players should land before reaching their flight time limit or they will crash to death.
  • Players are not able to enter shooting mode/map view before exiting flight mode.

Flight/Landing/crashing:

• The flight starts with a warning message about landing: Message text:"Avoid crashing by reaching the ground with minimal speed before your flight time is over"
• During the flight the height and speed will be displayed and changed dynamically:
• Landing alert message will be displayed 30 seconds before the flight time is over: Message text:"The jetpack fuel tank is almost empty! Land now or you'll crash to death"
• When the player has reached the initial height with no speed (and it is safe to land), a landing message will be displayed: Message text:"Press F to land and exit flight mode"
• If the flight time is over or the player tried to exit flight mode with some speed they will crash to death:
• The crash should look like the GIF below:

Map view:

• During the flight a flight modifier (jetpack icon) should be displayed above the player's marker (like the shooting mode modifier, see issue #62) Attached the Player's markers with the flight modifier: makers.zip
  • The player's marker should represent the current flight altitude.