Adds support for OS notifications, which I'll use to show errors handling URIs in a subsequent PR.

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Closes: #76

Adds basic support for `coder:/` URIs for opening RDP.

relates to #52 but I still need to add support for checking the authority.

Closes: #88

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Co-authored-by: Dean Sheather <[email protected]>

Closes: #94

Closes #50

Fixes #52

Checks for the authority string, i.e. `coder.example.com` in `coder://coder.example.com/v0/open/...` links matches the HTTP(S) URL we are signed into. This ensures that the names we use are properly scoped and links generated on one Coder deployment won't accidentally open workspaces on another.

I found the source of the issue where mutagen would fail to acquire the lock on `daemon.lock` at startup.

The MutagenClient attempts to lock the `daemon.lock` file while it is starting, so that it can fail fast if the daemon is not running.

While well meaning, this creates a race condition because as soon as we start the daemon process we create a MutagenClient so that we can talk to the daemon over its API. The MutagenClient might be holding the lock or have the lockfile open at the exact moment the daemon itself attempts to acquire and lock the file. The daemon immediately exits in that case and doesn't retry locking the file.

I've just removed the preflight checks on the `daemon.lock`, since we don't want Coder Desktop to ever mess with that file (outside of tests).