next: Revise record gear routes

[Steven-Chan]

proposal:

(change) /record/schema/access -> /record/creation_access/update (not existed yet) -> /record/creation_access/get /record/schema/default_access -> /record/default_access/update (not existed yet) ->/record/default_access/get /record/schema/field_access/get -> /record/field_access/get /record/schema/field_access/update -> /record/field_access/update

(no change) /record/schema/rename /record/schema/delete /record/schema/create /record/schema/fetch /record/fetch /record/query /record/save /record/delete

[Steven-Chan]

On the other hand, we may also consider revise the underlying record store (skydb) function name and comments. https://github.com/SkygearIO/skygear-server/blob/master/pkg/server/skydb/conn.go#L136

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The skydb SchemaAccessHandler also looks a bit strange. It decodes request payload to ACL, but the handler can only handle creation access.