## Summary
Refactor and enhance branding capabilities. Now branding is included
from a single directory that contains at least `strings.json`,
`manifest.json`, and `favicon.ico`. Any other assets may be placed in
the directory and will be copied to the bundled app.

Running the build as normal should show no difference.

Running the build with `BRANDING=./some-other-brand npm run start:dev`
will try to use a branding from the specified directory (that is relative to the
project's source root).

See `BRANDING.md` for more details.

Resolves: #1682

## Details
Branding changes:
  - Move Konveyor branding assets to a project top-level branding directory

  - Remove MTA branding assets

  - Remove profile/branding constants from `env` and client module

  - Embed branding strings and assets in the common module
    - `strings.json` is templated to allow the build to adjust asset
      URL path roots as necessary
    - `brandingAssetPath()`

  - server's index.html generation sources the template strings from the
    common module's branding strings

  - `HeaderApp` and `AppAboutModal` components support branding by using
    the `useBranding` hook

  - `BRANDING` as a relative path is computed from the project root

  - webpack build source branding assets directly from the common module

  - Unit tests, snapshots and jest configs updated as necessary

Jest changes:
  - Use `react-i18next` mock from `client/__mocks__` as a more robust mock
    borrowed from react-i18n repos

  - Move `setupTests.ts` into `client/src/app/test-config` to keep jest
    test config code all in the same directory

Related changes:
  - Upgrade rollup to v4, add new rollup plugins (copy, virtual)

---------

Signed-off-by: Scott J Dickerson <[email protected]>
Co-authored-by: Ian Bolton <[email protected]>
Signed-off-by: Cherry Picker <[email protected]>

Following up on PRs #1664 and #1739, downgrade to `rollup@^3.0`. The v4
of rollup has "native" code that runs the build, and that code does not
currently work with s390 builds [1]. Since konveyor is built for x86,
arm, ppc, and s390, all of those need to work.

When the s390 builds can work with the wasm bits, we can upgrade to
`rollup@^4.0` again.

[1] - rollup/rollup#5354

Signed-off-by: Scott J Dickerson <[email protected]>