Add string for space key

It always looked a bit odd in the input manager when the space bar was assigned somewhere.
Add keybinding helptext to more menus

This commit adds a short help text for these menus to show the correct key to open the keybindings menu:
* Construction menu
* New character (first tab only)
* Overmap
Slightly more reasonable default keybindings

NEXT_TAB in character creation can no longer be done with TAB, because this is already used by gender,
so you could get stuck in the profession tab by switching tabs with TAB, which may be confusing.

Random names (character and world) are now using “*” instead of “?” to allow the keybinding menu to appear on “?”.
Show actual keybindings in world manager name tab
Cosmetic edit to default keybinding file

“SPACE” instead of “ ”, simply to be more consistent
Let the mod manager show the actual keybindings
Reserve world names “TUTORIAL” and “DEFENSE”
Use different font color for special saves

In this case, “TUTORIAL” and “DEFENSE”.
refactored season length calculation for consistency
SDL: Add TARGETTEXTURE to the required rendered flags

Without this, SDL might chose a renderer that does not support rendering to a texture.
This makes SDL_SetRenderTarget fail later.
Make a dedicated draw_sidebar function:

contains all the stuff that is printed in the sidebar:
HP,
monsters,
mini map,
messages,
character status,
...
stop accounting for initial season
because new game initialization already sets us in the proper turn
some other random fixes
removed sun from night time
it was weird to have sunny nights, so I made sure that doesn't happen by adding a check (to the sun's wallet)
Make some forgotten strings translatable

The forgotten strings:
- “You: <text>” in NPC talk menu
- Strings in item spawn group debug menu
- “Description: <text> in mod manager
Fix adv. inventory sorting texts not being translated
Fix effect name and desc. not being translated
Bugfixes in field.cpp game.cpp init.cpp
 Fixed unused vars, double initialization, iterattors changed to auto.
Bugfixes item.cpp mapgen.cpp melee.cpp monattack.cpp mondeath.cpp...
Fixed unuser vars, fix return c_str() when std::string in declaration
Fixed wrong conditions in item and monattack.
Bigfixes overmap.cpp player.cpp trapfunc.cpp weather_data.cpp
Fixed allways left leg in trapfunc, unused vars and redundant condition
Fix bug of input action not being translated