Translate and rename user interface functions

[VladimirMakeev]

Description of Changes

• Give proper names and translate some user interface related functions;
• Game settings flags were moved to a separate class with properly named access methods;
• Variables storing current mouse coordinates and button state were renamed;
• Variable used for setting up style of dialog shown by F0_1238_001e_ShowDialog was changed to a enum with comments about possible values.

Rationale behind Changes

Code cleanup, translation.

Suggested Testing Steps

Check these menus and dialogs, they should work as expected:

• Dialog asking player to enter its name at the start of the game;
• 'Top' menu bar with all its menus: 'Game', 'Orders', 'Advisors', 'World' and 'Civilopedia';
• 'Game' menu (shortcut Alt+G) with its 'Options' submenu;
• 'Find city' dialog (shortcuts ?, /) and its logic;
• 'Advisors' menu (shortcut Alt+A) with all its options;
• Dialog asking player to enter a custom city name after settlers had build it.

Mouse should also work as expected.