docs: use Ignite CLI for Starport

[jaybxyz]

Description

closes: #307

Tasks

• [x] Rename Starport to Ignite CLI in all documentation

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• [ ] Code follows the module structure standards.
• [ ] Wrote unit and integration
• [ ] Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• [ ] Added relevant godoc comments.
• [ ] Re-reviewed Files changed in the Github PR explorer
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