CONFIG: Snabba upp processen Travis gör

[Eightquake]

CONFIG: Improve Travis checks and processes

Currently, we are using Husky hooks to make sure tests pass and every file is linted before committing changes. Then, when we add a Pull Request to merge those changes, Travis runs the same tests to make sure they pass and then lints the code again. After that, it tries to pack the electron application and then discards it all.

All in all, a PR check takes a few minutes, which is required for a merge.

Could the Travis process be improved and sped up somehow?

[Eightquake]

After PR #378, the Travis config is a bit different.

It can still be improved on though! Here are some thoughts on it:

• Combine linting and testing into one job, so they use the same npm install and don't have to do it separately
• Move the environment variables from available to all branches to master only, so that electron-builder doesn't do codesigning when it isn't needed (like for package stage, which could cut down on some minutes)
• Maybe only use one Travis, not both of them?