feat: consolidate static and elastic scheduling strategy

[D-D-H]

Currently, Jifa supports two types of clusters:

• static: all worker nodes are fixed and started up in advance. A static worker node has self-storage.
• elastic: worker nodes are scheduled dynamically based on k8s. The storage is shared between master nodes and worker nodes.

This feature introduces a hybrid type to consolidate these two types so that a Jifa cluster can have static and elastic worker nodes at the same time. The location of a new file is decided by the rules (see FileLocationRuleEntity).

This feature doesn't eliminate the storage limitation(which could be a follow-up feature):

• static worker nodes have an independent storage.
• master and elastic worker nodes share shared storage.

[y1yang0]

Looks good