Separate View and Edit for Key-Value Section of UI

Currently, there is only an "edit" mode when clicking through the Key / Value section of the Consul UI.

#### Feature Description

The standard in other HashiCorp product UIs is to default to a "read" view and then have an "edit" button if the user wants to /change/ the value rather than just see it. Of course, read/edit/delete actions should be subject to ACLs.

#### Use Case(s)

Consistency across HashiCorp product UIs, helping customer expectations and adoption curve.

Start at the Consul UI Key / Value section and trace how its current edit mode is entered. Review the existing ACL behavior, then define completion as a default read view with an explicit edit action and read/edit/delete actions respecting ACLs.

Written by the indexing model from the issue text.