Reduce the size of loopback client bundle

[bajtos]

At the moment, a browserified loopback module has about 1.4MB uncompressed, 650KB compressed. This size is unacceptable, especially for mobile browsers on a slow internet connection. We need to get at least below 100kb.

This GH issue is a time-scoped story. The goal is to analyse the dependencies, fix as many low-hanging fruits as possible and then create follow-up stories for the unsolved items.

Subtasks:

• Remove all usages of lodash loopbackio/loopback-datasource-juggler#538 - remove lodash
• browser: remove packages used by server only strong-remoting#187 - remove js2xmlparser and cors
• Import subset of underscore.string scripts only #1246 - optimise underscode.string usage
• Remove usages of "crypto" module in browser #1247 - rework places using crypto module
• User passwords in the browser #1249 - don't use bcryptjs in browser
• Browser-Request doesn't work in most browsers strong-remoting#177 - use a smaller HTTP client in the browser
• Client plug-ability for browser based HTTP agents #1211 - pluggable HTTP client
• Investigate if we can get rid of "buffer" usage in the browser

[BerkeleyTrue]

@bajtos any advice or strategies on this?

[bajtos]

My plan is to produce profiling data using file (bundle) size instead of execution time, so that we can identify the files and modules that contribute most to the overall size. There may be an existing browserify module for that, I did not check yet. (Please let me know if you figure out how to do this.)

Once we have that information, it should be easy to pick the biggest dependencies, check if they are used by the browser client, and exclude them using browser field in the relevant package.json field if they are not needed.

[BerkeleyTrue]

So the first step is to get the size of each file/script in the bunde?