Ability to run build scripts before docker builds

[asalkeld]

Describe the solution you'd like

This could be in the project definition (nitric.yaml)

buildScripts:
 - yarn install

Why is this needed? What challenge will it help you solve? Please describe.

There are often commands needed to be run before a docker build, it would be great to have a mechanism to say "please run this command before doing the docker build"

Describe alternatives you've considered

We have to run this manually and document it.

[raksiv]

This requires a conversation before we have anything to action.

[raksiv]

Options include exposing a docker file which can be edited Consider hot-reloading Might need a convention which can be overwritten

[raksiv]

Keeping the docker file hidden with defaults should also be available.

[tjholm]

Will be implemented as part of defining custom docker files