T3T1 support, space saving, GH actions emulators

[grdddj]

Support for T3T1 emulators

Decreasing the size of Docker image

Getting latest/main emulators from GH-actions

TODO: remove the temporary commit and load GH_TOKEN from env

[grdddj]

In the end, getting the latest core emulators from trezor.io --- still depending on Gitlab for legacy and arm builds.

@vdovhanych I am already satisfied with this, can you please approve the small Dockerfile changes? It is just setting up Poetry garbage collection and moving all the RUN steps into one layer - which both make the image smaller.

I did quite a lot of experiments with decreasing the image size, with the idea of deleting as much nix-connected stuff as possible.

• the majority of almost 4GB image is taken by stuff from /nix/store, which is however hard to delete, as it is needed for the app to run
• I tried to get rid of it with e.g. nix-collect-garbage -d, nix-store --gc or nix-store --optimize - which helps in theory when run in the running container - but in the image phase, it deletes something, just to have it installed again when starting the application
• One possibility is to convert the Dockerfile to start with ubuntu/debian base image - I tried it, it is possible to get the size around 1GB - however, I was experiencing issues with running the latest emulators and with bridges ... but this I guess is the ultimate way of making the image more user-friendly regarding the size and startup time (especially for Suite CI - @Nodonisko)
• It is certainly possible to somehow decrease the size while keeping the nix base image - e.g. build the application in one build-stage and then copy just it into another runtime-stage ... this article seems to be the best I read, which however utilizes flake.nix instead of shell.nix --- https://mitchellh.com/writing/nix-with-dockerfiles

There are two upcoming tasks/TODOs:

• remove the hardcoded trezor-emu-core-T3T1-v2-main-arm emulator, when it will be available from Gitlab CI - from https://gitlab.com/satoshilabs/trezor/trezor-firmware/-/jobs/artifacts/main/download?job=core%20unix%20frozen%20T3T1%20debug%20build%20arm
• replace custom trezorlib installation with official one after new release - @matejcik - the custom installation from trezor-firmware repo takes more than a gigabyte of space in the image

[vdovhanych]

If we do not use the download option from GitHub then its fine like this, but read my comment for that.

[Nodonisko]

@grdddj As I said I don't see that much benefits from using Nix inside of Docker image so I vote for removing it.

[vdovhanych]

Im already working on simple alpine image without nix, should be third the size

[Nodonisko]

@vdovhanych Nice thanks! Every saved MB here = saved few minutes of runtime in total across all our CI jobs