Add Shavit_StopReplay & Shavit_GetClientReplayBot natives

[mariokeks]

There was previously no clean way to stop a replay bot:

• For Replay_Central bots, there was no way to stop one at all. Forcibly kicking it would leave it missing for up to several seconds until the cron timer respawns it.
• For Replay_Dynamic bots, the only option was KickClientEx to kick the bot in the same frame.
• For Replay_Prop bots, the only option was RemoveEdict, which destroys the prop and bypasses Shavit_OnReplayEnd. OnEntityDestroyed, which handles Replay_Props that mysteriously die, only kicks them (KickReplay) rather than finishing them (FinishReplay)

/**
 * Stops the playback of a replay bot.
 *
 * @param bot                       The replay bot entity.
 * @param client                    Client requesting the stop, or 0 to bypass the permission check.
 * @return                          True if the replay bot has been stopped, false otherwise.
 */
native bool Shavit_StopReplay(int bot, int client = 0);

• Either a simple check if a client has a active replay bot or a way to get further information of the active replay via the replay bot entity.

/**
 * Retrieves the replay bot (or prop) entity currently tied to a client.
 *
 * @param client                    Client index.
 * @return                          Replay bot entity, 0 if no replay bot is active.
 */
native int Shavit_GetClientReplayBot(int client);

[rtldg]

Looks rightish but I didn't test