Add amx_searchcmd command in adminhelp plugin and do some clean up (#415)

* AdminHelp: Use semicolon everywhere

* AdminHelp: Translate amx_help description

* AdminHelp: Use the available ADMIN_ALL define in register_concmd

* AdminHelp: Bind the cvars

* AdminHelp: Replace %L by %l

* AdminHelp: Remove task only when necessary

* AdminHelp: Reorder some lines to prepare next commit

* AdminHelp: Use read_arg_int() on the first argument and clamp the value

* AdminHelp: Use read_arg_int() on the second argument and clamp the value

* AdminHelp: Rename few variables and callback

* AdminHelp: Use constants for buffers max length

* AdminHelp: Add amx_searchcmd command, and update the multilingual file

* AdminHelp: Adjust spacing a little for readability

* AdminHelp: Add amx_help_display_msg_time cvar

* AdminHelp: Add the new command in the help message (and fix missing return)

* AdminHelp: Add a check if provided entry no. goes above the total found entries

* AdminHelp: Don't show the help message for begin if all commands are already displayed

* AdminHelp: Make sure the server command use amx_help_amount_per_page value

configs/amxx.cfg

@@ -156,6 +156,11 @@ amx_language_display_msg 1
 // Default value: 1
 amx_help_display_msg 1
 
+// Time to wait (in seconds) before displaying a message about amx_help to a client once joined the server
+//
+// Default value: 15
+amx_help_display_msg_time 15
+
 // Amount of commands per amx_help page
 //
 // Default value: 10