pass Vault token back to requesting application instead of storing it in browser session

[sichen1234]

Please change the vault identity UI authorization screen to pass the Vault token back to the requesting application instead of storing it in the browser session. This is the standard process for OAuth that we should also follow.

The vault identity UI authorization screen should take as parameters:

• Name of calling application
• Return URL with string ${vaultToken}

It should then ask the user to authenticate by saying "Please authenticate access for ${Name of calling application}." Once the user authenticates, it should return the Vault token as a parameter of the ${return url} , replacing ${vaultToken} with the actual vault token.

Vault token should no longer be stored in browser session storage.