Upgrade to .NET 8 planned

[shibayan]

Acmebot v4

Upgrade to .NET 8 using Azure Functions functionality, previously called the In-Process model. We believe that the upgrade will be relatively seamless, requiring no major changes. There will be no major feature additions associated with the upgrade.

• https://techcommunity.microsoft.com/t5/apps-on-azure-blog/net-on-azure-functions-march-2024-roadmap-update/ba-p/4097744

Acmebot v5 (planned)

The next major update will be in Acmebot v5. On the implementation side, a new programming model called .NET Isolated in Azure Functions will make it easier to support future .NET 10 LTS.

Significant functionality additions are planned for v5. Specifically, multi-subscription, multi-key vault, and multi Azure DNS Zone support.