Refactor index files

[slifty]

This PR improves our index.html in two ways:

1. We no longer have environment-specific index files, instead having just one with angular environments determining which dynamic values / tokens to use.

2. We no longer include vendor code in our index file, instead registering it as a dependency which is inserted via angular.

This is much cleaner and easier to maintain.

Resolves #885

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 47.76%. Comparing base (4aeb05e) to head (73d81f2).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #887      +/-   ##
==========================================
- Coverage   47.79%   47.76%   -0.03%     
==========================================
  Files         351      351              
  Lines       11292    11292              
  Branches     1889     1889              
==========================================
- Hits         5397     5394       -3     
- Misses       5702     5708       +6     
+ Partials      193      190       -3     

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[slifty]

@cecilia-donnelly @aasandei-vsp I ran this locally and kicked off a dev build -- it appears to be working as expected locally (inspecting I see the config properly injected in an environments object)

Dev is harder to parse since things are minified, but I see index.html is much smaller / linking the external js and the application itself works, so that's a great sign.

It would be worth invoking something that would trigger NewRelic and confirming that the action had the expected effect on NewRelic from dev.

---

ALSO PLEASE NOTE: this adds a new project dependency, and so you will need to re-build your web-app image.

[aasandei-vsp]

This is not my area of expertise, but I tried at least to take it locally and see if it works and I get the following error:

• I ran npm in web-app, and ran again docker compose

[aasandei-vsp]

Some questions:

• How do we test it on the upper env?
• Is there any pipeline change necessary?

[slifty]

@aasandei-vsp the error you're seeing is related to that note I added in the end of the comment above ALSO PLEASE NOTE: this adds a new project dependency, and so you will need to re-build your web-app image.

You have to blow away the image and rebuild because our docker containers don't update their installations of npm dependencies on start. This is an augmentation we should make since it so regularly causes issues, but it isn't in scope for this specific PR.

---

For testing in other envs I did deploy to dev and it worked (I don't think there's a great way to test in other envs outside of the deploy cycle, but seeing it work in dev is a good sign)

[aasandei-vsp]

Made it work locally, thanks @slifty for the help!