feat(scopes): introduce typed scopes

[Litarnus]

Replaces one Scope and introduces a total of 3 scopes:

• GlobalScope - Cannot store spans but can store user data such as tags, contexts, etc
• IsolationScope - Can store spans and is used to store request local informations
• MergedScope - Transient scope that is the result of merging the global and isolation scope. Is considered a read-only scope and should only be used to apply data to events

Why different types of scopes?

With only one type of scopes, the burden of knowing when to merge and which one to use where is passed to the developer all the time. While it would work with any scope and it would apply some informations, it's very easy to forget to merge scopes and only get a fraction of the required informations. With having specific types, the signature can ensure that the correct scopes are being used in the correct context. It's also easier to understand intent.

The scopes also expose different methods, meaning that it's impossible to add data to a merged scope which gets discarded afterwards.

All scopes share a common ScopeData object which acts as a data storage to simplify merging/cloning. ScopeData is effectively what was the Scope before but without event specific methods