Maintain Install Guide for Arm Performix

[jai-adam-schrem]

This maintenance PR for the Performix install guide learning path addresses the following:

• Originally, the install guide included sections on preparing & adding targets via both the GUI & CLI, which had become out of date (for example, we now support password authentication). Also, there were some nuanced details missing regarding the types of targets we support - the code hotspots recipe is supported on Windows on Arm and x86 Linux targets. To resolve this for the long-run, I have removed all information about preparing & adding targets from this learning path, and have instead redirected readers towards the Performix User Guide for further information, which is always kept up to date & fully maintained. Removing this duplicated info from the install guide learning path should make maintenance easier going forwards.
• There was an incorrect path for amd64 Linux installs, now corrected
• Clarified that the installation instructions vary by host platform (not target platform) for the avoidance of confusion
• Added guidance on how to add the apx binary to path for easier CLI usage for host operating systems other than Linux, as the CLI does support other operating systems
• Mentioned the MCP server which is imminently landing as a feature and will enable a completely new way to access Performix alongside the existing CLI and GUI

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