Start to decouple dom completely from vdom

[matt-gadd]

Type: feature

The following has been addressed in the PR:

• There is a related issue
• All code has been formatted with prettier as per the readme code style guidelines
• Unit or Functional tests are included in the PR

Description:
As we start to explore other targets such as native, we need to begin decoupling the dom parts from vdom. In the future we can hopefully make vdom have some kind of agnostic "node" structure to work with, but for now that is too big of a change. So this is a small refactoring that allows the user to pass a node api (that similarly maps to the equivalent dom operations) to the mount function.

This would for instance then allow the user to write adapters for writing to something non dom like.

Down the line we'd still have these issues:

• middleware that works on raw dom nodes (I have changed the core node middleware to use the passed nodeApi but generally the same change would have to happen elsewhere
• the current api gives no more context than the existing dom api's, which may not be sufficient when writing api's for other targets
• the current api closely matches the dom equivalents which are extremely dom centric

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[codecov]

Codecov Report

Merging #883 (1da8941) into master (34f2645) will increase coverage by 0.00%.
The diff coverage is 97.67%.

@@           Coverage Diff           @@
##           master     #883   +/-   ##
=======================================
  Coverage   94.52%   94.52%           
=======================================
  Files         127      127           
  Lines        8020     8094   +74     
  Branches     1876     1888   +12     
=======================================
+ Hits         7581     7651   +70     
- Misses        439      443    +4     

Impacted Files	Coverage Δ
src/core/vdom.ts	97.77% <97.67%> (-0.18%)	⬇️

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