Recover Goblint server automatically after crashing

[karoliineh]

While working on my thesis it has been very annoying that the plugin crashes each time I misspell the file name in the configuration file or make a syntax error in the .c file. This PR will try to make the plugin able to recover from most of those cases where Goblint crashes during analysis, so one does not have to restart the plugin manually.

• [x] When Goblint crashes due to No such file or directory and Goblint conf is changed, the plugin will try to restart.
• [ ] Try to restart the plugin when Goblint crashes due to a parsing error.
• [x] Notify the user when the new configurations were not read in due to a mistake in the configuration file (e.g. syntax error or missing option).

[karoliineh]

For now, I will merge this PR without implementing the server recovery for when Goblint crashes due to parsing errors.

That is because this PR already fixes a lot of bugs and therefore I want this to be merged ASAP. Implementing server restart when files have parsing errors requires either:

1. Acquiring the analysed files list from Goblint with pre_files, remembering them and watching for modifications in those files after Goblint has crashed. This is not ideal, though, because it does not work if the parsing errors are in the files already before Goblint manages to analyse them for the first time.
2. Making a PR for MagpieBridge to have an alternative method of analyze, that, instead of giving a list of files that have been opened since the start of the latest IDE session, would also/instead give a list of only saved/modified files (since the last analysis). Also related to and could be used for #17.

These both require more time for implementing than I have right now, so this will (hopefully) be another PR in the future.

• [x] This PR additionally fixes the issue of the plugin getting stuck waiting for the socket during launch.