refac(context): Refactor to make execution context optional for components

[mikeproeng37]

Summary

• Aims to simplify the construction of the top level components by removing the executionContext from the required path
• Renames some of the option functions to the new paradigm where they are prepended with With
• Important caveat to note is that now we have to explicitly call the Start methods of the PollingConfigManager and QueueingEventProcessor

Test

• Unit

[thomaszurkan-optimizely]

Should Start be part of the EventProcessor interface?

[pawels-optimizely]

if you ran the example (end-to-end) and it's not hanging because of wrong ExeContext then it looks good.