Vryx poc anchor

[bianyuanop]

This PR implements an action based anchor registry where users are free to register/update/delete an Anchor on SEQ, where rollup info related to it will be recorded. The current AnchorInfo spec:

type AnchorInfo struct {
	FeeRecipient codec.Address `json:"feeRecipient"`
	Namespace    []byte        `json:"namespace"`
}

The AnchorRegister action spec

type AnchorRegister struct {
	Info      hactions.AnchorInfo `json:"info"`
	Namespace []byte              `json:"namespace"`
	OpCode    int                 `json:"opcode"` // 0 -> create, 1 -> delete, 2 -> update
}

Future work & Questions

• Permissioned access for AnchorRegistry such as only admins are allowed to register
• Naming of the AnchorInfo struct, since it's more related to the metadata of a rollup, should we change it to RollupInfo?