"az keyvault secret set" have many parsing errors

## Description
"az keyvault secret set" have many parsing errors, when a value have special characters. For example the command have problem with ")", ">", "&" and ...?

Example Command:
**az keyvault secret set --name test --value ')aaa@aa>:{&aaa'**

## To Reproduce:
Simply try to add a secret with some special character from above.

## Workaround
You can put every special character in quotation marks ("), but no idea how many characters are affected.

Example Workaround:
**az keyvault secret set --name test --value '")"aaa@aa">":{"&"aaa'**

## Environment Summary
```
Windows-10-10.0.18362-SP0
Python 3.6.8
Installer: MSI

azure-cli 2.19.1 *

Extensions:
aks-preview 0.5.6
alertsmanagement 0.1.0

```