Fix patching & Frida script

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The latest Anker app version (3.21.1) has broken the patching script and seems to have introduced yet more anti-tamper mechanisms.

This PR:

• Fixes the patching of the smali code in patch.sh to make it work again.
• Bypasses the new anti-tamper mechanism by intercepting C calls to process exit and freezing the security thread.
• Adds a new patch_2.sh script which uses a different mechanism to inject Frida into the app.
• Updates the documentation for app patching to be more specific.