This commit brings in considerable amount of work. When working on this issue everything was so tied together, that I have abandoned all attempts to split it into multiple commits. There are following changes and more:

* Implementation of lightweight chroot for containing the application in single directory tree.
* Design changes in scripts and daemons to implement the lightweight chroot.
* Many configuration file changes to make everything work properly.
* Makefile additions, new targets related to running
* Updated development documentation page.

(Redmine issue: #4216)

(Redmine issue: #3387)

(Redmine issue: #3387)

(Redmine issue: #3387)

In case empty message was loaded from the message queue error was logged into the log file, but event for fetching next message from the queue was not scheduled, which basically resulted in halting of the message processing.

This was done to better decouple the library code. I have also added logging of subject and recipients for each email and added makefile target for launching development mail server. (Redmine issue: #3443)

(Redmine issue: #3443)

(Redmine issue: #3361)

This feature can be very usefull for turning off certain unwanted application or module features. For example one might want to use some kind of module implementing password authentication, but block the account registration endpoint provided by that module. (Redmine issue: #4781)

This means, that when running in production environment with logging to email enabled system administrators will be immediatelly notified about the error. (Redmine issue: #4769)

Previously some HTTP errors like Forbidden or Unauthorized returned HTML even for API endpoints. This was due to the fact, that they were executed by built-in code. I have rewritten the error handling code to be smarter and detect the appropriate response type based on client preferences. I have also consolidated and unified the error response generation. There is a new submodule hawat.errors, that contains the error response generation code and both core error handlers and AJAXMixin/HTMLMixin classes use that. I have also merged all the HTML error page templates into single one. (Redmine issue: #4769)

(Redmine issue: #3387)

Currently only built-in Flask commands run, shell, etc. are available. It can be used to launch development web server, which is now documented in development documentation page. (Redmine issue: #4216)

The logging setup is now more capable and configurable. (Redmine issue: #4216,#3443)

(Redmine issue: #3387)

There were issues with local .gitignore and commit:14be3783 does not by mistake contain the actual module code. (Redmine issue: #4220)

I have used Pylint tool to fix easily fixable issues. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

The original name was unnecessarily long. (Redmine issue: #3443)

To be more consistent with the rest of the system this patch moves the built-in index page to separate pluggable module. There is still room for improvement by using Jinja2 macro for rendering breadcrumb navigation. Currently it is used only within part of the system. (Redmine issue: #4220,#3443)

This commit brings in basic filtering rule playground view, that enables users to simply paste IDEA event as raw JSON string and then write and immediatelly check filtering rule againsta that event. Possible improvements are better integration with filters.show, filters.create, filters.update and events.show views. (Redmine issue: #4745)

Changed coding style to match the rest of the project, added some more configuration options for tweaking authentication modules, like default login/logou redirection targets. (Redmine issue: #3443)

Reason is better reuse in other projects. (Redmine issue: #4216,#3387)