Add reflect lib for auto generation

[wsquan171]

This PR is a continuation of previous work by @annakhm on test-reflect branch on the following aspects.

Functional

• Support conversion of primitive schema types: int, bool, string
• Support conversion of nested schema types: list, set
• Nested struct in sdk model should be represented as list with at most 1 element, with metadata SchemaType set to struct
• List or set of primitive data types (int, bool, string) should use *ExtendedSchema as Schema.Elem
• List or set of struct data types should use *ExtendedResource as Schema.Elem, and set Metadata.ReflectType to the type of element type in the slice, rather than a slice type.
• UT under metadata/metaddata_test.go can be referenced as example use cases.

Non-Functional

• Refactored reflect code into own package for adding isolated UT
• Moved version check logic to utils package, so both nsxt and metadata package can share the code
• Added Github action for UT

TBD in a future PR

• Support of polymorphous struct or list of structs
• Support of Schema.TypeMap

[wsquan171]

/test-all

[wsquan171]

/test-all

[annakhm]

Lets make sure we cover the following use cases, either in unit tests or with a resource:

• list of native types (int, string, bool)
• set of native types
• list of structs
• set of structs
• pointer to struct in the model (list of with maxItems = 1)
• double-nested struct or list of structs
• list of polymorphic structs (next PR)
• set of polymorphic structs (next PR)
• pointer to polymorphic struct (next PR)

[wsquan171]

/test-all

[wsquan171]

/test-all