chore: remove .NET7, bump packages

[followynne]

@mo-esmp

This PR aims to:

• remove support for .NET 7 from Serilog.Ui.Web
• bump Nuget packages (and release a new minor version for affected packages)
• release new majors version for Postgres - MongoDB - RavenDb providers, due to changed frameworks/referenced SDK with breaking changes
• restore MongoDB tests functionalities

Let me know if you have any doubt otherwise I'll close the PR as soon as you approve it and release the latest versions 🛩️

[mo-esmp]

Thanks for the PR. Regarding package updates, how are dependencies and versions managed now that the *.nuspec files are no longer used?

[followynne]

@mo-esmp

They get automatically calculated using the . csproj and the Build.props files - the same happens with the different project properties 😁

If you try to upload on Nuget an old package with nuspec and one with the current setup, you'll see that the data are calculated precisely on the prj files. (you can do the same test by packaging 2 versions and inspecting the resulting files)