Allow patch spec.Project in templatePatch

[sergeimonakhov]

Summary

Allow patching spec.Project through templatePatch. Currently, this is prohibited, but there are cases when there is no access to either the ApplicationSet or the Application object, and in such cases, it is safe.

Motivation

Dynamically generate the project name using a full-fledged Go-template.

Proposal

Add some kind of unsafe flag or parameter in the config to allow patching.