Support for Flatpak/.deb/Appimage

[dnet890]

Hi
I appreciate that Linux support snap version. But, not everyone likes snap. Is this possible to support Flatpak/.deb/Appimage?

[tinywrkb]

I've looked at this a while back, when there wasn't a Linux binary release, and got back to this today.
What I noticed first, is that there's no much value of the desktop app currently, as network is required during startup (bookmarks disappearing on startup), and there's no multi-account support, so what's the point?

Anyway, I did look at packaging this, so let's continue.

The second thing I noticed is that this doesn't build. It was obvious in my previous attempt, but now I had to dig in the strace output to figure it out, and it seems like in my previous attempt a few months back, the problem is that sentry-cli is failing, likely due to a missing SENTRY_AUTH_TOKEN environment variable.
So building from source is not possible, or at least I haven't succeeded in doing so.

Going with option number 2, repackaging the binary release, as option 1, building from source, failed. It's definitely possible, and the app does run, but

1. If I can avoid it, I will not repackage snaps. Give me a tarball release or deb package, as those I can extract without adding dependencies like squashfs.
2. Why sandboxing is disabled? Render processes should be sandboxed, especially when this app is not limited to the webapp service, and opens whatever URL that was saved by the user.
3. No aarch64 builds?
4. There's no license here or in the webapp repo. At least explicitly give redistribution authorization, so we could pull the app into Flathub's Flatpak repository with the benefits of delta downloads and downloading all artifacts from Flathub's repo, instead of using an extra-data source, which downloads the app from an external/third-party server (so not Flathub) during local (end-user) installation, a crafty trick to work around missing redistribution authorization, but not without disadvantages.
5. app.asar should be unpacked, which is much better for Flatpak as its deduplication is file based.

Back to my opening, with the current state of the app, I'm not really interested in submitting the app myself, but having gone into the trouble of packaging it, I can help with the initial submission to whoever wants to submit and maintain it.

p.s. This is my WIP. There's a lot in it that not relevant and will have to be dropped or change, as I was experimenting, I wasn't sure if I will build from source, and what type of binary release will be used. That being said, the manifest should build for you and run.

edit: Minor wording and grammar changes.

[RokeJulianLockhart]

@dtantono, flatpak support split into #39 (comment).