Support for type rename + aliases

[lvca]

Types should be able to be renamed. For example to rename the vertex type "Chat" into "Case":

• rename() in ComponentFile class
• rename the underlying file prefix, leaving untouched after that Chat_0.14.65536.v0.bucket -> Case_0.14.65536.v0.bucket
• update the entries in LocalSchema class (bucketMap)
• update the entries in FileManager class (fileNameMap)
• at the end, save the schema

Also:

• support multiple aliases can be used to lookup for the type. This helps with refactoring, so the old queries still work.
• support new SQL syntax alter type XX aliases YYY, ZZZ