Release 1.9 iptables wrapper

[changluyi]

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What type of this PR

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• Features
• Bug fixes
• Docs
• Tests

Which issue(s) this PR fixes:

Fixes #(issue-number)

WHAT

🤖 Generated by Copilot at 9a26853

This pull request updates and refactors the iptables management for the project, using a newer go-iptables library and adding support for nft mode. It also adds a new utility function for parsing iptables rules with double-quoted comments.

🤖 Generated by Copilot at 9a26853

Oh we are the iptables crew, we work with rules and chains
We split the strings and parse the fields, we migrate and maintain
Heave away, me hearties, heave away with me
We'll make the gateway node secure, with go-iptables library

HOW

🤖 Generated by Copilot at 9a26853

• Replace the outdated dependency on github.com/coreos/go-iptables with the updated fork github.com/kubeovn/go-iptables (link,link,link,link)
• Add a new field iptablesObsolete to the Controller struct, and initialize it with the legacy mode iptables instances if the iptables works in nft mode (link,link)
• Add two helper functions to check the iptables mode by evaluating the symbolic links of the iptables commands (link)
• Import the "path/filepath" package to use the filepath.EvalSymlinks function (link)
• Remove some obsolete iptables rules that are no longer needed for the gateway node, and rename the variable abandonedRules to obsoleteRules (link,link,link)
• Define some constants for the iptables table, chain and comment names, and assign the iptables instance to a local variable ipt (link,link)
• Add a new function cleanObsoleteIptablesRules to delete the obsolete iptables rules in the legacy mode, and clear the obsolete iptables chains (link)
• Add a new function deleteObsoleteSnatRules to delete the obsolete SNAT rules for the gateway node, and call it in the setIptables function (link)
• Add a new function DoubleQuotedFields to split a string into fields by spaces, but preserve the double-quoted parts as a single field, and use it to parse the iptables rules that contain double-quoted comments (link)