Hellper does not ask for a Incident Title in the opening form

[GLOFonseca]

Subject of the issue

When an incident is opened, we insert the channel name in the title column in the Postgres.

This is wrong, there is the Incident Title and the Incident Channel Name.

We need the Incident Title in the database when an incident is closed. So we can create the PostMortem doc with the proper title.

Steps to reproduce

1. Open an incident with /hellper_incident
2. Check the postmortem document
3. Check the incident on Postgres

Expected behaviour

• The opening form should ask for an Incident Title, not only a Channel Name.
• The title column should be filled with this Title
• The title in the postmortem document should have this Title, not the Channel Name.

Actual behaviour

We use the Channel Name from the opening form for everything, the title column, the `channel_name column and the postmortem title.

Possible Solution

Create a new field on the opening form called Title, and use this value to save in the title column. And after that use this column to fill the postmortem title.