Update Supported Modules Definition

[maxime-rainville]

Supported Modules Definition hasn't been updated in a while.

It references outdated concept like addons. All our other policies are stored in the developer docs as well.

Acceptance criteria

• Supported module definition is moved to the developer doc.
• Old page redirect to the new page.
• Outdated concept are removed.
• Clear guidance is provided in terms of what kind of level of testing, security support and CI can be expected for supported modules with links to related policies.

Useful links

• https://silverstripe.atlassian.net/wiki/spaces/CMS/pages/3201007665/2024-03-12+Supported+module
• https://silverstripe.atlassian.net/wiki/spaces/CMS/pages/3238723585/2024-04-10+Supported+module
• https://silverstripe.atlassian.net/wiki/spaces/CMS/pages/3196977412/2024-02-28+Product+Workshop

Note

• This is about documenting the status quo as it exists in practice. To the extent that the status quo could be improved upon, raise a follow up card.

Related card

• https://github.com/silverstripeltd/product-issues/issues/815