Overhaul Restrict Weapons plugin - part 1 (#347)

* Restmenu: Use CS_OnBuyAttempt forward to detect any buy attempt - part 1

- Removed any useless code which won't be needed anymore with forward. A lot!

* Restmenu: Use CS_OnBuyAttempt forward to detect any buy attempt - part 2

- Added the actual forward
- Because of forward passing a CSI_* constant, it's needed to refactor how is saved a blocked item. Not fully implemented everywhere because menu is going to be refactored later as well.

* Restmenu: Replace findAliasId() by cs_get_item_id()

* Restmenu: Use cvar pointers

* Restmenu: Refactor menu - part 1

Purpose:
  - Convert old menus to new menus.
  - Instead of having one menu with several pages, having one main menu (item types) and sub-menus (items list). More readable, more easy to naviguate and no pagination.
  - Move hardcoded strings to ML

* Restmenu: Refactor menu - part 2

Purpose:
  - Convert old menus to new menus.
  - Instead of having one menu with several pages, having one main menu (item types) and sub-menus (items list). More readable, more easy to naviguate and no pagination.
  - Move hardcoded strings to ML
  - Minor visual improvements

* Restmenu: Refactor podbot stuff

- Factorized code
- Used a more direct way to set restrictions

* Restmenu: Refactor load/save config file

- Used new file natives
- Moved harcoded message header to ML
- QoL: saved restricted items will be grouped per type
- Cleaned up few things

* Restmenu: Refactor amx_restrict command

- Minor improvements on how are retrieved/handled arguments from command.
- Same as menu, it displays first classes list, then it lists associated items. No more pagination.
- Minor visual changes.

* Restmenu: Remove unused stuffs

* Restmenu: Move more harcoded messages to ML

* Restmenu: Move MAPSETTINGS define to cvar

- Don't forget me in changelog
- There is room for improvements but for now keep the same behavior

* Restmenu: Add some consistency, no code change

- Renamed some variables
- Changed functions order
- Removed extra spaces
- Fixed leading tabs

* Restmenu: Use inline formatting at various places

* Restmenu: Make command descriptions multilingual for player

* Restmenu: Refresh opened menus if the command is used to save/load/set.

Also, I've removed the renaming of "exit" item because it was misleading as it returns MENU_EXIT when it's named with "back" and handling the action wiht that doesn't make much sense.

* Restmenu: Adjust minor things (consistency, readability, safety)

* Restmenu: Show the current category when items are listed through the command

* Restmenu: Display admin activity on loading/saving

+ load: reset blocked items only if file has been loaded
+ load: ignored if no arguments
+ save: added a silly fix because of the cvars

configs/cstrike/amxx.cfg

@@ -210,3 +210,9 @@ amx_statsx_duration 12.0
 // Default value: -2.0
 amx_statsx_freeze -2.0
 
+// Sets whether Restrict Weapons plugin should use a configuration file per map or or not.
+// If enabled, the file format is: weaprest_mapname.ini (e.g. weaprest_de_dust.ini).
+// -
+// Default value: 0
+amx_restrmapsettings 0
+