Clean up dependencies and baseline specification

[LinqLover]

• IMAPClient-Core depends on IMAPClient-UI, which is generally a bad symptom:

  

  Maybe this would be even worth a regression test (see also PackageDependencyTest).

• IMAPClient-Core and IMAPClient-Protocol depend reciprocally on each other. I don't know whether this is an architectural problem, but it might be worth another thought, even because the dependency from Protocol on Core is only manifested by a single method (ICParser >> #parseFetchHeader:withId:).

• In the baseline, these dependencies are not specified! This is an actual problem because other packages that depend on IMAPClient will have to specify them manually. If they only depend on the Core package, its dependencies won't be resolved.

  See this pair baseline for an example of how to use and declare dependencies: https://github.com/LinqLover/TelegramSmalltalkBot/blob/03be8437dfd9b9e98715d4fcc42fcea13cc90ae4/src/BaselineOfTelegramSmalltalkBot.package/BaselineOfTelegramSmalltalkBot.class/instance/baseline..st#L15 https://github.com/LinqLover/SimulationStudio/blob/5a0ddad75130e947a270bc6dd0ab7e3b0aa4e562/packages/BaselineOfSimulationStudio.package/BaselineOfSimulationStudio.class/instance/baseline..st#L14-L15