Add timeout to warm gittar cache step

[ymekuria]

Closes #314

Background

Sometimes the installation or upgrade of the zkapp-cli hangs during the warm cache for project template step in the postinstall.js file when a network request is made by gittar to fetch the zkapp-cli templates and examples from github here.

Approach

This PR adds a timeout to the fetch gittar operation. If the fetch operation does not resolve before the the timeout, the warm cache for project template step is skipped, and the installation continues. See this discussion for more details.

Next steps

A log was added to show which NPM packages were added to the cache in the warm NPM cache for project template deps step. A log was also added before the gittar fetch operation in the warm cache for project template step. We can use these logs to gain better visibility into hanging operations in the future and adjust the approach to addressing them accordingly.

[jasongitmail]

Important for an eng reviewer to actually pull this branch to test it please

[nicc]

Looks good. Tested locally by dropping the timeout to 1ms and installing from my branch.
fyi to see the relevant logs I had to npm install with --verbose --foreground-scripts

[ymekuria]

fyi to see the relevant logs I had to npm install with --verbose --foreground-scripts

Interesting @nicc. Were you able to see other logs from the postinstall.js file without the --verbose --foreground-scripts flag?