Add SysTypes According to Zones

[arshadd-b]

SysTypes are different across Zones.
Refer here #15

[arshadd-b]

/assign

[arshadd-b]

Hi @dharaneeshvrd @Karthik-K-N
To handle SysTypes according to zone i am thinking to keep map of Zones where key will be zone and value will be list of SysTypes

Sample structure

"dal": {
		Description: "Dallas, USA",
		VPCRegion:   "us-south",
		COSRegion:   "us-south",
		Zones: map[string]Zone{
			"dal10": {SysTypes: []string{"s922", "e980"}},
			"dal12": {SysTypes: []string{"s922", "e980", "s1022"}},
		},
		VPCZones: []string{"us-south-1", "us-south-2", "us-south-3"},
	},

We have to change the logic in these below functions

ValidateZone
ZoneNames
RegionFromZone
AvailableSysTypes

there are no parameters changes in these function except AvailableSysTypes
In AvailableSysTypes currently we just take region as a parameter now with new change we have to add zone as well
So to get sysTypes we need both region and zone

Also I have checked where these functions are getting used
Since in only one function AvailableSysTypes where we are changing the signature and this function till now is not getting called anywhere

So I don't see major impact
Please let me know your thoughts
Thanks