feat(installer): add default install directory with existing install …

[LaurenceJJones]

…detection

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Description

• Default to /opt/pangolin for new installations
• Check current directory and /opt/pangolin for existing installs
• Prompt to use existing install if found at default location
• Offer to change directory ownership when running via sudo
• Create installation directory if it doesn't exist

How to test?

Currently the installer generates files relative to where the installer is ran, ultimately this creates:

• User confusion on where the files ended up
• Documentation struggles since there is no "default directory" for user to follow if they want to make changes
• User might generate in a folder and ask "How do I move this?"
• Might cause user to accidentally place in a folder that has broad permissions and causes information exposure.

The intended direction of this PR is to standardize the output location so moving forward users can get a sense of where files will be generator and create a standard of where we would like them to be placed.