ASA Go: Notification Message Refinements

As fire staff, I want to see a greater detail in the header of an advisory/warning notification so I can see at a glance the most important info first.

**Describe the task**
These notifications, which have three different lengths, are currently not showing enough detail until the whole content is read. It would be more practical to raise the most relevant info in a header at the top of the message, showing for both the short lock screen notifications, and the longer in-app ones.

**Acceptance Criteria**
- [ ] Header indicates severity of issue (warning or advisory)
- [ ] Indication of Rate of Spread
- [ ] Critical times are shown

**SME/User Contact**
Erik, Neal, Jessica, Andrew

**Additional context**
- The question was raised whether the Fire Centre is needed, as the Fire Zone already suggests the FC it is a part of.