[Cosmos] [API Review] Rename CosmosContainer to Container

[ealsur]

1. Rename type CosmosContainer struct to type Container struct
2. Rename type CosmosContainerProperties struct to type ContainerProperties struct
3. Rename type CosmosContainerRequestOptions struct to type ContainerRequestOptions struct
4. Rename type CosmosContainerResponse struct to type ContainerResponse struct

All methods that mention CosmosContainer in their name should be Container, like:

func (c *CosmosClient) GetContainer(databaseId string, containerId string) (*Container, error)

instead of

func (c *CosmosClient) GetCosmosContainer(databaseId string, containerId string) (*CosmosContainer, error)