[CU] Update assets icon structure and make icon names app agnostic

Description of Change

Updated assets package icon structure
- Renamed svgs folder to icons
- Moved the VA logo to its' own folder (VALogo) outside the icons folder
- Moved the DoD branch emblems to their own folder and renamed to be more generic (serviceEmblems) for if non-military service emblems are added eventually (e.g. NOAA)
- Flattened other folders' icons to just be flat in the icons folder
Renamed:
- Logo → LogoWhiteText (redesign of flagship login screen will necessitate a separate logo with black text or a new SVG with configurable text color)
- ProfileSelected → AccountCircle
- BenefitsSelected → Description
- BenefitsUnselected → DescriptionOutline
- PaymentsSelected → FileInvoiceDollar
- PaymentsUnselected → FileInvoiceDollarOutline
- HomeSelected → Home
- HomeUnselected → HomeOutline
- HealthSelected → MedicalServices.svg
- HealthUnselected → MedicalServicesOutline

A separate PR will be needed to integrate changes into Icon component/components package.

Nothing to test, just rename/restructure.

Code reviewer validation:

General
- [x] PR is linked to ticket(s)
- [x] PR has changelog label applied if it's to be included in the changelog
- [x] Acceptance criteria:
  - All satisfied or
  - Documented reason for not being performed or
  - Split to separate ticket and ticket is linked by relevant AC(s)
- [x] Above PR sections adequately filled out
- [x] If any breaking changes, in accordance with the pre-1.0.0 versioning guidelines: a CU ticket has been created for the VA Mobile App detailing necessary adjustments with the package version that will be published by this ticket
Code
- [x] Tests are included if appropriate (or split to separate ticket)
- [x] New functions have proper TSDoc annotations

If changes warrant a new version per the versioning guidelines and the PR is approved and ready to merge: