Requirement changes: errors & status

[purrplingcat]

Implement requirement changes in restmodel. Changes are improved in these issue:

Caloriosa/caloriosa#3

Quick change list:

• INVALID_SENSOR status removed
• INVALID_*, PASSWORD_REQUIRED has now HTTP status code 422
• Added new status DATA_PARSE_ERROR used insteadof INVALID_DATA for invalid or incomplete - JSON or when error occured while parsing JSON.
• INVALID_DATA used for data validation (field formats, structure and etc) and now has http status 422
• Added MISSING_REQUIRED for validation check, when required fielad is aquired in POST, PUT, PATCH input JSON
• BUSY now has http status 429 insteadof 503
• UNKNOWN renamed to SERVER_ERROR and changed message to "Internal server error"
• DATA_INCOMPLETE removed. It's now useless
• Removed ACTIVATION_FAILED. Use INVALID_DATA instead if used wrong or already used activation token
• Removed PASSWORD_MISMATCH. Password match validation while user registration is checked on client-side
• Removed OK status. List is now ONLY error statuses!
• ... and more

It's a original issue, but edited. Please read it carefully!

[CallMeFoxie]

Should be mostly done via latest commits, will see if we hit some discrepancy.