Successful edit to route back to the detail view with the toast confirmation

[sandysage]

Description

When editing an entry, I want to be certain that the credentials have been successfully updated.

This can be supported by the following methods:

• That I'm routed back to the read-only view of the login detail, upon completing my edit (as opposed to the login list)
• That I see a confirmation toast at the base of the login detail

Designs

Zeplin: https://zpl.io/bJgxpzn

Icon: success-icon.zip

[changecourse]

Designs added to description above, unblocked and good to go.

[eliserichards]

Related to #1161