feat: add a new way of specifying which command(s) to run, and in what order

[kenotron]

Currently, one has to do:

just-scripts build

to run 1 command. We can get rid of the need of lots of just.config.ts in monorepo packages if we an allow for multiple commands done:

just-scripts [transpile,copy-resources]
just-scripts [transpile,copy-resources]<>[asdf]

Or something similar