Change directory for clab created files to `/tmp/clab`

Makefile changed to create /tmp/clab folder if not present. Run containerlab from within /tmp/clab.

Description

Since the clab-gosdn_csbi_arista_base directory (created by containerlab with sudo) was messing with gopls and go.mod this has been changed to create this folder in another directory.

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.