Towards web standards 🎖️

[ap-justin]

Closes BG-1563 Towards BG-1530

Explanation of the solution

• switch from location.state to search params e.g. _s, which is available to loaders
• switch from marketplace context to search params
• separate header containers (but reused contents) for home, app, admin pages

Instructions on making this work

• run yarn or yarn install to install npm dependencies
• run yarn run test --watchAll to verify all tests still pass
• (optional) run yarn run build to verify the build passes
• run yarn start to start the webapp

UI changes for review

When major UI changes are introduced with a PR, please include links to URLS to compare or screenshots demonstrating the difference and notify on design changes

[linear[bot]]

BG-1563 Endowments can edit allocations

BG-1531 DRAFT : Upgrade web-app to modern rendering pattern

[linear[bot]]

BG-1530 Can we lock Better Giving logo on left side of admin screens?