chore(dev): add virus scanner npm install to root install command

[justynoh]

Problem

npm install in the root directory only performs package installation for the frontend and backend, even though npm run dev attempts to run the frontend, backend and virus scanner services.

Solution

Add virus scanner package installation into the root postinstall step.

Breaking Changes

• No - this PR is backwards compatible

[KenLSM]

Im thinking that this shouldn't be added to root as virus-scanner is not required to build the image for formsg

[justynoh]

hmm, but by that logic, the frontend install also shouldn't be included in root install right haha 😅 or am i missing something

[KenLSM]

ccmiw

github: build FormFE && FormBE
eb: upload FormFE to s3 (after env configs are in)
eb: run FormBE

Although I think we can install them separately after we have achieved the split deployment of FE & BE

[justynoh]

oh, this was more from a DX perspective haha. if you clone the repo fresh, npm i npm run build:frontend and npm run dev, the last command fails because it attempts to start virus scanner without having installed it's packages first. not so much from deployment perspective

that being said, the npm i does influence deployment speed. But i think the number of packages in the virus scanner isn't that much, the impact to deployment should be negligible. in comparison, the frontend install takes significantly longer haha