feat: add sha512sum to checksum registry and add notices

[42atomys]

Description

Introduce the sha512Sum function as requested by sprig community and update old functions to new standards (naming convention and notice for deprecation) to checksum registry

Changes

• Add sha512Sum function to checksum registry
• Add error return to each method of the registry
• Add notice to deprecate old naming sha1sum -> sha1Sum

Duplicate of https://github.com/Masterminds/sprig/pull/400, https://github.com/Masterminds/sprig/pull/326

Checklist

• [x] I have read the CONTRIBUTING.md document.
• [x] My code follows the code style of this project.
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.
• [x] I have updated the documentation accordingly.
• [ ] This change requires a change to the documentation on the website.

Additional Information

Documentation update are embed

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Files	Coverage Δ
registry/checksum/checksum.go	92.3% <100.0%> (+7.6%)	:arrow_up:
registry/checksum/functions.go	100.0% <100.0%> (ø)