Simplify Release Management on OSCAL Github repo and website (#1264)

* Migrated most release notes to the Github releases page for easier maintenance.

Co-authored-by: Alexander Stein <alexander.stein@nist.gov>

CONTRIBUTING.md

@@ -59,10 +59,10 @@ There are two mailing lists for the project:
 
 Contributions can be made to the following branches in this repository:
 
-- **release-\***: The release branches are used to provide patches to a major or minor version of OSCAL. The branches are named release-*major*.*minor*. You should provide changes only to the highest numbered *minor* release for a given *major* release. Patch releases are made more frequenly than *major* or *minor* releases.
+- **release-\***: The release branches are used to provide patches to a major or minor version of OSCAL. The branches are named release-*major*.*minor*. You should provide changes only to the highest numbered *minor* release for a given *major* release. Patch releases are made more frequently than *major* or *minor* releases.
 - **develop**: This branch is used to queue changes for the next *major*/*minor* release of OSCAL. A *major*/*minor* release will result in the creation of a new release branch, once the development has been completed and the update is to be staged for release.
 
-More information about how releases are managed in this repository can be found in the [versioning and branching guide](./versioning-and-branching.md).
+More information about how [releases](../../releases) are managed in this repository can be found in the [versioning and branching guide](./versioning-and-branching.md).
 
 The OSCAL project uses a typical GitHub fork and pull request [workflow](https://guides.github.com/introduction/flow/). To establish a development environment for contributing to the OSCAL project, you must do the following:
 

README.md

@@ -6,15 +6,15 @@ NIST is developing the [Open Security Controls Assessment Language](https://csrc
 
 With this effort, we are stressing the agile development of a set of *minimal* formats that are both generic enough to capture the breadth of data in scope (controls specifications), while also capable of ad-hoc tuning and extension to support peculiarities of both (industry or sector) standard and new control types.
 
-The [OSCAL website](https://www.nist.gov/oscal) provides an overview of the OSCAL project, including an XML and JSON [schema reference](https://pages.nist.gov/OSCAL/docs/schemas/), [examples](https://pages.nist.gov/OSCAL/resources/examples/), and other resources.
+The [OSCAL website](https://www.nist.gov/oscal) provides an overview of the OSCAL project, including an XML and JSON [schema reference](https://pages.nist.gov/OSCAL/reference/), [examples](https://pages.nist.gov/OSCAL/concepts/examples/), and other resources.
 
 If you are interested in contributing to the development of OSCAL, refer to the [contributor guidance](/~https://github.com/usnistgov/OSCAL/blob/main/CONTRIBUTING.md) for more information.
 
 ## Project Status
 
-To view the latest release of OSCAL check out [GitHub releases](/~https://github.com/usnistgov/OSCAL/releases). The [release notes](https://pages.nist.gov/OSCAL/reference/release-notes/) are also available on the NIST OSCAL website, and contain a summary of the changes between the different releases.
+To view the latest release of OSCAL check out [GitHub releases](../../releases). Each release on that page provides a complete summary of the changes made in each release.
 
-All changes are made based on the excellent feedback and contributions that are received from the OSCAL community. The NIST OSCAL team is very thankful for all of it.
+The changes made in each release are based on the excellent feedback and contributions that are received from the OSCAL community. The NIST OSCAL team is very thankful for all of it.
 
 Any feedback may be emailed to the NIST OSCAL team at [oscal@nist.gov](mailto:oscal@nist.gov) or by [creating an issue](/~https://github.com/usnistgov/OSCAL/issues) on the GitHub repository.