temp dir override for hauler store load

[amartin120]

Please check below, if the PR fulfills these requirements:

• Commit(s) and code follow the repositories guidelines.
• Test(s) have been added or updated to support these change(s).
• Doc(s) have been added or updated to support these change(s).

Associated Links:

Types of Changes:

• Feature

Proposed Changes:

• By default hauler store load temporarily copies the contents of its haul to the OS's default TEMP directory in order to maintain an existing store's contents should it exist.

  • On Unix systems, the default is $TMPDIR if non-empty, else /tmp.
  • On Windows, the default is GetTempPath, returning the first non-empty
    value from %TMP%, %TEMP%, %USERPROFILE%, or the Windows directory.
  • On Plan 9, the default is /tmp.

• Added a new flag to hauler store load called --tempdir or -t that allows the user to override that value if they do not have the ability to modify the ENV that normally controls that.

❯  hauler store load --help                                                                                                                                                                                                                                                                               ─╯
Load a content store from a store archive

Usage:
  hauler store load [flags]

Flags:
  -h, --help             help for load
  -t, --tempdir string   overrides the default directory for temporary files, as returned by your OS.

Global Flags:
      --cache string       (deprecated flag and currently not used)
  -l, --log-level string    (default "info")
  -s, --store string       Location to create store at (default "store")

Verification/Testing of Changes:

• When overrode via the new flag, the supplied directory is used for temp.
• When omitting the flag, the normal OS temp dir is used just like today.

Additional Context: