Timon

Bump to Python 3.11+ (drop support for olders)

Features
- 77 Better messages for HttpJsonProbes
- 78 80 Web interface have the worst status color in the column header
- 83 Web interface: Add a worst status counter in column headers
- 87 Add HttpJsonTimeoutProbe that permits checking the timestamp in a json
- 91 Add paranoia-loop (-p) to the run command
- 92 Add Timon Plugins
- 92 97 101 Add an Http Server Plugin
- 98 100 Add a Db store for probe results and probe status changes
- 104 Add an extra field in probe config for all extra data unused by probes

Bugs
- 81 Set probe status to ERROR instead of UNKNOWN for http response statuses differents of 200 and 404
- 86 Fix Web Interface Notifications
- 88 Fix ClientCACheck with TLS 1.3
- 89 Fix don't fail if hprobes is None
- 102 Fix notifiers that crash timon

Coding style / CI
- 83 Web interface refactorisation of table population
- 95 Cleanup: change from print to logs
- 103 Remove trio framework and use asyncio only

Features
- 43 + 53 now there's a --pdb and a --pdb-hook switch
- 70 + 72 add flap detection
- 64 add timeout for subprocess probes to avoid too long freezes
- 44 notifiers no more compulsory
- 66 add retry for isup probe
- 65 + 67 add timeout detection for webif
- change isup timeout
- allow sub second delays for shell loop

Bugs
- 71 fix rsrc limits (introduced during refactoring)
- 72 fix http probe bugs (url_params, ...) + tests
- 68 fix scheduler bug
- fix cert bug for async requests
- 61 fix increasing timeout
- 52 fail interal was not dumped properly

Testing
- 51 attempts for debugging / testing the scheduler

Coding style / CI
- 47 refactor probe initialisation
- 49 old coroutine / yield syntax has been removed
- 58 coding style check now for isort
- 57 use github actions for CI
- 59 add isort check for CI. no flake for pypy
- 46 refactor resources and modernize some code

* Probe: OneUrlHttpJsonIntervalProbe (a value has to be in a certain range)
* Probe: ClientCA Probe. to whether servers accept client certs
* Webif: Notification permission requested when loading page (and not at first notif)
* Notifier: Posting request to external url
* fixing some package meta data
* fixed setup for gitlab-ci runners
* fix CI runners (enter and leave subdirs)
* flake fixes
* cleanup. rename var (double reversed logic)

- web-if: servers in table view can be grouped
- a prebuilt version of the web interface is now part of the repository
- resource limits can be set via env vars
- robustify web-if: server notification
- robostify web-if: handling of missing hosts
- add helper to build webif
- update some node dependencis for web-if
- some code cleanup for python and js

New features:
- Has now a simple first (passive) web front end.
- CI improvements
- flake8 for python code
- jslint for web code
- use pytest for testing
- use travis for github
- has also a gitlabci file for gitlab hosting