Add EP on Build Strategies Parametrization

This covers the use case introduced in issue
shipwright-io#184

This also will provide an enhancement in the current Build API, by
migrating existing fields into a more readable/understandable path.

docs/proposals/parameterize-strategies.md

@@ -0,0 +1,124 @@
+<!--
+Copyright The Shipwright Contributors
+
+SPDX-License-Identifier: Apache-2.0
+-->
+
+---
+title: Parameterize Build Strategies
+authors:
+  - "@qu1queee"
+reviewers:
+  - "@SaschaSchwarze0"
+  - "@ImJasonH"
+  - "@sbose78"
+approvers:
+  - "@adambkaplan"
+creation-date: 2021-03-25
+last-updated: 2021-02-09
+status: implementable
+---
+
+# Parameterize Build Strategies
+
+TBD
+
+## Release Signoff Checklist
+
+- [ ] Enhancement is `implementable`
+- [ ] Design details are appropriately documented from clear requirements
+- [ ] Test plan is defined
+- [ ] Graduation criteria for dev preview, tech preview, GA
+- [ ] User-facing documentation is created in [docs](/docs/)
+
+## Open Questions [optional]
+
+TBD
+
+## Summary
+
+TBD
+
+## Motivation
+
+TBD
+
+### Goals
+
+TBD
+
+### Non-Goals
+
+TBD
+
+## Proposal
+
+TBD
+
+### User Stories [optional]
+
+TBD
+
+#### Story 1
+
+#### Story 2
+
+### Implementation Details/Notes/Constraints [optional]
+
+TBD
+
+### Risks and Mitigations
+
+TBD
+
+## Design Details
+
+### Test Plan
+
+TBD
+
+### Graduation Criteria
+
+TBD
+
+#### Examples
+
+TBD
+
+##### Dev Preview -> Tech Preview
+
+TBD
+
+##### Tech Preview -> GA
+
+TBD
+
+**For non-optional features moving to GA, the graduation criteria must include end to end tests.**
+
+##### Removing a deprecated feature
+
+TBD
+
+### Upgrade / Downgrade Strategy
+
+TBD
+
+### Version Skew Strategy
+
+TBD
+
+## Implementation History
+
+TBD
+
+## Drawbacks
+
+TBD
+
+## Alternatives
+
+TBD
+
+## Infrastructure Needed [optional]
+
+TBD