updates the migration order
fixes unit test
reverts the notion of shema migration - we will run migrations normally as we've been doing, this fixes a couple of unit tests too.
Adds migration to rename the index umbracoUserLogins_Index to IX_umbracoUserLogins_Index so that it follows standards, fixes unit test
Fixes: U4-4373 @Library.NodeById(-1).Id returns "0" instead of "-1"(6.2.0 beta)
Fixes: U4-4373 @Library.NodeById(-1).Id returns "0" instead of "-1"(6.2.0 beta) & U4-4374 @Model.NodeById(-1).DescendantsOrSelf().First().Id results in Excecption (6.2.0 beta)
Fixes: U4-4427 Exception with selecting content start node in Multi-node tree picker 6.2.0
Fixes: U4-4368 Cannot insert the value NULL into column 'name' when creating new relation type from API
Fix Null Prevalue Values on Export of DataTypes

Exporting a DataType that has a Numeric pre-value that has no value
causes an Exception - added null checking to pre value.value
Merge remote-tracking branch 'origin/6.2.0' into 7.1.0

Conflicts:
	src/Umbraco.Core/Persistence/Migrations/MigrationRunner.cs
	src/Umbraco.Core/Persistence/Migrations/Upgrades/TargetVersionSixTwoZero/AddChangeDocumentTypePermission.cs
	src/Umbraco.Core/Persistence/Migrations/Upgrades/TargetVersionSixTwoZero/AdditionalIndexesAndKeys.cs
	src/Umbraco.Core/Persistence/Migrations/Upgrades/TargetVersionSixTwoZero/AssignMissingPrimaryForMySqlKeys.cs
	src/Umbraco.Core/Persistence/Migrations/Upgrades/TargetVersionSixTwoZero/UpdateToNewMemberPropertyAliases.cs
	src/Umbraco.Core/Umbraco.Core.csproj
	src/Umbraco.Tests/Umbraco.Tests.csproj
	src/umbraco.controls/TreePicker/SimpleContentPicker.cs
Fixes merge issues