Support developing applications that use multiple individual containers

[krzychb]

Jaguar works by loading the application into a separate container, but it only runs one at a time. We start installing the program here https://github.com/toitlang/jaguar/blob ... r.toit#L49 (this is what kills the old version of the program) and we start running it here https://github.com/toitlang/jaguar/blob ... r.toit#L60.

This issue is suggesting to implement a new feature to load the applications into individual containers identified by the name: <App name> from https://docs.toit.io/platform/apps/appspec/#the-specification-file

Inspired by https://esp32.com/viewtopic.php?f=2&t=24941#p88621

[kasperl]

Being able to develop apps that run across multiple containers using Jaguar seem useful.

[kasperl]

@krzychb Finally made some progress with this. Once #228 lands, you can install multiple containers and have them run side by side using:

$ jag container install hello examples/hello.toit
$ jag container install http examples/http/http.toit
$ jag container list
718b6ac6-860c-58af-8ef7-f694e7284dc6: jaguar
0b777bc9-d58c-56b2-a030-1738f48888b1: hello
6173c8b0-be07-5b2e-852a-1e9cc5847a3a: http

[krzychb]

Thank you @kasperl!