Allow stored leases to specify renewable status

Problem/Motivation

The module currently assumes that all stored leases are renewable. This may not always be the case. Non renewable leases throw a client error when a renewal is attempted.

Steps to reproduce

Obtain dynamic lease from vault_aws_kv using a federated token.

Proposed resolution

Add the ability to specify if a lease is renewable when storing. Check renewal flag before attempting renewal.

Remaining tasks

User interface changes

API changes

Client will now accept if lease is renewable (default to TRUE for BC)
Lease Storage must now accept a renewable field.

Data model changes

Lease storage plugins will now need to store a renewable flag.