Add a new cvar as `gal_text_messages_mute` (gal_sounds_mute)

[evandrocoan]

Add a new cvar as gal_text_messages_mute (gal_sounds_mute)

Create a new cvar as gal_text_messages_mute based on the gal_sounds_mute principle.

// Indicates if any sounds should be muted during the various events in
// which they'd normal be spoken.
// The flags are additive. A value of 0 will not mute any of the sounds.
// 1 - "get ready to choose a map"
// 2 - "7", "6", "5", "4", "3", "2", "1"
// 4 - "time to choose"
// 8 - "runoff voting is required"
gal_sounds_mute 0

For example, setting it to disable this message below, would require an if over it.

File: Galileo\scripting\galileo.sma
4053:     // visual countdown
4054:     set_hudmessage( 0, 222, 50, -1.0, 0.13, 0, 1.0, 0.94, 0.0, 0.0, -1 );
4055:     show_hudmessage( 0, "%L", LANG_PLAYER, "GAL_VOTE_COUNTDOWN", g_pendingVoteCountdown );

-->

File: Galileo\scripting\galileo.sma
4053:     // visual countdown
4054:     if( !( get_pcvar_num( cvar_textMessagesMute ) & VISUAL_COUNTDOWN ) )
4055:     {
4056:         set_hudmessage( 0, 222, 50, -1.0, 0.13, 0, 1.0, 0.94, 0.0, 0.0, -1 );
4057:         show_hudmessage( 0, "%L", LANG_PLAYER, "GAL_VOTE_COUNTDOWN", g_pendingVoteCountdown );
4058:     }