Create Proof Request button in Proof Template not working/implemented

[schlagtim]

When opening a proof template the "Create Proof Request" button is always disabled (See ProofTemplateView.vue).
The button functionality is not implemented which needs to be done.

When clicking on the "Create Proof Request" button a view should open which offers selection of one of the available partners to send the proof request to. In that selection there should be a "Submit" button which is only active when a partner is selected.

[schlagtim]

To keep UI consistent a new tab can be created "Proof Requests" with a flow similar to "Credential Issuance".
In this view display all requested proofs filtered in a table. Above should be a component similar to the one in "Credential Issuance" (a.k.a. dropdown, select partner with "Send with invitation", select proof template, JSON-LD switch is not necessary). A popup dialog like in Credential Issuance is not necessary.

In "Proof Templates" view remove the "Create Proof Request" button.