Adds new APIs with major refactor

What's Changed

• Add C2B URL registration by @weezqyd in #25
• Refactor: remove identifiers by @jwambugu in #26
• Refactor tests - use shared context by @jwambugu in #28
• Add dynamic qr api #29 by @jwambugu in #38
• Add constants for different parameters by @jwambugu in #39
• Add Transaction Status API #30 by @jwambugu in #40
• Add Account Balance API by @jwambugu in #41
• Update README.md by @jwambugu in #44
• Use uber style guide and housekeeping #42 by @jwambugu in #43
• Refactor endpoints by @jwambugu in #46
• Add business pay bill by @jwambugu in #47
• Update docs and extract constant types by @jwambugu in #48

New Contributors

• @weezqyd made their first contribution in #25

Full Changelog: v1.0.7...v1.0.8