ByteAether.Ulid.linq2db NuGet introduced

[Seramis]

Description

• Introduced ByteAether.Ulid.linq2db for registering Ulid type to LinqToDB. Supports all .NET versions from 6.0 to 10.0. Deliberately depends on the LinqToDB version 6.0.0 allowing end-user's newer version to "upgrade" it to their version.
• Moved MSSQL Guid shuffling code into a shared DB.Shared project. Used by both LinqToDB and EF Core projects. Did same for tests, moving them into DB.Shared.Tests project.
• Reorganized solution folders slightly. Both LinqToDB and EF Core project folders are now under commong DB folder.
• Refactored CodeQL GitHub Actions workflow. Now contains list of projects once and then uses this list to restore and build each of them.
• Added and updated documentation. Included minimum version of LinqToDB as well as EF Core into documentation as badges.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Other (please specify):

Checklist

• The PR is submitted to the correct branch (main).
• My code follows the project's coding style. (.editorconfig)
• I have commented my code, particularly in hard-to-understand areas and public interfaces.
• I have added or updated tests for the changes I made.
• All new and existing tests passed.
• I have updated the documentation where applicable.