Use separate Babel configuration for Jest

[gusevda]

What changed?
Separate Babel configuration babel.config.testing.json was added in this PR for being used only for testing by Jest. Tests specific configuration includes @babel/preset-env preset that is not needed for Parcel builds. From the default Babel configuration this preset was removed.

Why was this change made?
This change was made to deal with warnings that Parcel displays during build process:

@parcel/transformer-babel: Parcel includes transpilation by default. 
Babel config babel.config.json includes the following redundant presets: @babel/preset-env. 
Removing these may improve build performance.

  weave-gitops/babel.config.json:4:13
    3 |         [
  > 4 |             "@babel/preset-env",
  >   |             ^^^^^^^^^^^^^^^^^^^
    5 |             {
    6 |                 "targets": {

  💡 Remove the above presets from babel.config.json
  📝 Learn more: https://parceljs.org/languages/javascript/#default-presets

[casibbald]

Ace!
I tried to fix this but did not get anywhere with it