Fixed event message in Publisher

[Limraj]

Description
If there are html/script tags in the event message, then scripts from the message are executed. Event messages should be encoded.

To Reproduce

1. Login as admin;
2. Create Virtual Data Source as ds_1 (enable, update: 1s), and Virtual Data Point as dp_1 (numeric, random, settable, enable);
3. Go to 'Publishers';
4. Select 'Http Sender' and click on 'Add';
5. Set name 'pub_1', and url: 'http://google.pl/', check 'Raise result warning';
6. Select 'ds_1 - dp_1' in 'Points' and click on 'Add', and click on 'Save';
7. Go to 'Publishers', and enable 'pub_1';
8. Click edit 'pub_1' -> error
   

Spec:

• Scada-LTS Version <=2.7.5.3