🎁 A great TypeScript upgrade for BaseModel that really ₁₂₃ Counts

This release brings some great updates to the BaseModel class.

First, a TypeScript update to aid in development, especially when using TS-friendly editors: #487. Thank you, @hamiltoes, for a great update!

Next comes the count and countInStore methods with their accompanying getter, actions, and a matching renderless data component. @fratzinger did the community a great favor by giving this little-known FeathersJS feature a more visible API in feathers-vuex.

Many many thanks from the entire community to @fratzinger and @hamiltoes for the very supportive and highly-comprehensive PRs.