This PR implements the new policy transforms feature, which allows
policy packs to not only issue warnings and errors in response to policy
violations, but actually fix them by rewriting resource property state.
This can be used, for instance, to auto-tag resources, remove Internet
access on the fly, or apply encryption to storage, among other use
cases.
Add support for using Ctrl+O to open the current update in the browser
for backends that support permalinks.
The keybinding is advertised in the interactive display as part of the
message that displays the permalink:
```
Previewing update (dev)
View in Browser (Ctrl+O): https://<some-url>
Type Name Plan
+ pulumi:pulumi:Stack vpc-dev create
+ ├─ aws:ec2:Vpc vpc create
+ ├─ aws:ec2:SecurityGroup secgroup create
+ ├─ aws:ec2:SecurityGroupRule rule-2 create
+ ├─ aws:ec2:SecurityGroupRule rule-0 create
+ ├─ aws:ec2:SecurityGroupRule rule-1 create
+ └─ aws:ec2:SecurityGroupRule rule-3 create
```
In order to maintain backwards compatibility with older versions of the
Automation API, the message is not changed for non-interactive
scenarios.
Replace direct interaction with the terminal with an abstraction. This
abstraction is tightly constrained to the capabilities needed for the
CLI's display. Using this abstraction allows for straightforward testing
of the interactive renderers.