Use newer algorithm for name generation

Currently a SHA1 hash is used for name generation as a stable fallback if TargetName cannot be bound.

While not specifically used in a security context we should look at replacing this with a newer algorithm or an alternative as SHA1 is generally not recommended.

This may break suppressions because suppression is often done by name.

Also is overkill and could be confusing to have a name as long as a SHA512 so we should truncate the name, or provide some option for configuration related to the number of characters used for name generation.

In lead up to this breaking change we could provide the algorithm as a choice to allow configuration.

https://github.com/microsoft/PSRule/blob/5967ec1ded80e3354acc88d0f94b96f94d49beaf/src/PSRule/Pipeline/PipelineContext.cs#L64-L73