Draft: feat(repo): implement web flag

Created by: pbnj

Description

Implement -w|--web flag on repo command to open repo in browser

Related Issue

Relates to #405

How Has This Been Tested?

• go build cmd/glab/main.go
• ./main repo -w

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)
• Documentation
• Chore (Related to CI or Packaging to platforms)