Minor improvements to build process and startup scripts

[abhahn]

Motivation and Context

This PR makes 2 main changes:

1. Change vite build options to not overwrite the static directory on build, which can cause custom images to be removed from this folder if they have been added.
2. Create an option to skip the build in the startup scripts to save time if only making config or backend changes. The option is additive, so current users of these scripts will not notice the change unless the new option --skip-build is provided on the command line.

Contribution Checklist

• I have built and tested the code locally and in a deployed app
• For frontend changes, I have pulled the latest code from main, built the frontend, and committed all static files.
• This is a change for all users of this app. No code or asset is specific to my use case or my organization.
• I didn't break any existing functionality 😄

[abhahn]

Moving docs to a separate PR, and abandoning startup script changes for now since a best practice for building with custom logos has been identified.