Unit4 Expenses

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- Add new feature to create expense within claim
- Fix Add Claim button is missing after logout
- Fix app crash when taking photo for the first time
- Add error notification message when failed to create new expense
- Improve security on SQL Data Injection
- Improve security by using SHA 256 hash
- Fix insecure random number generator
- Add code obfuscation
- Improve security on logging sensitive data
- Encrypt data stored on device
- Improve security on file upload