Naming

I am just starting with the library and my comments may be premature. I haven't touched Go for an year now, so not sure the community has changed their view on conventions. But I found the naming is bit verbose, and add noise.

If I look at the types, we know the context is `GraphQL type`, so not sure we need to attach `GraphQL` to everything

```
GraphQLObjectType -> ObjectType or Object
GraphQLConnectionDefinitions -> ConnectionDefinitions
GraphQLSchema -> Schema
GraphQLResolveInfo -> ResolveInfo
GraphQLString -> String
...
```

```
GraphQLFieldConfigMap -> FieldConfig

```

as we don't need to add the data type it holds to.

Also quickly looking through the doc

```
type GraphQLInterfaceType
func NewGraphQLInterfaceType(config GraphQLInterfaceTypeConfig) *GraphQLInterfaceType
func (it *GraphQLInterfaceType) AddFieldConfig(fieldName string, fieldConfig *GraphQLFieldConfig)
func (it *GraphQLInterfaceType) GetDescription() string
func (it *GraphQLInterfaceType) GetError() error
func (it *GraphQLInterfaceType) GetFields() (fields GraphQLFieldDefinitionMap)
func (it *GraphQLInterfaceType) GetName() string
func (it *GraphQLInterfaceType) GetObjectType(value interface{}, info GraphQLResolveInfo) *GraphQLObjectType
func (it *GraphQLInterfaceType) GetPossibleTypes() []*GraphQLObjectType
```

typically you don't prefix the getters with `Get`, so they will be like `Description(), Error() , Name()`, or may even export the fields.

Let me know yours and @sogko 's thoughts on this. I could try a PR for if you agree.

thanks
bsr.