control flavors list based on priority

[swaroopar]

Add UI changes related to https://github.com/eclipse-xpanse/xpanse/issues/1577

• [ ] Show flavors based on priority numbers. It must in increasing order of the priority
• [ ] If no priority info available, then display in the same sequence that is received from backend.
• [ ] if some flavors have priority information, then first display them and then display the rest of flavors.
• [ ] in scaling, disable the lower priority (in the API this is the opposite. Priority 1 has highest priority) flavors.

[Alice1319]

I’ll take this.