Set default timezone per user

• Changed the default behaviour when posting a raid without specifying a timezone to use the game's server time instead of the host machine's local time.
• Users can now change the default behaviour for themselves by using the !timezone command. (This command takes a tz database name as argument.) Type !help timezone for examples. The syntax is not very user friendly but considering it will only be used by raid leaders and likely only once by them, I reckon that's fine.
• Everyone can still overwrite the default behaviour by supplying a time zone.

Localization

Bugfixes:

• Updated the French localization file for the changes in 3.5.2

3.5 second patch

Bugfixes:

• Created a workaround for an issue with the dateparser library when scheduling raids that occur within a few hours.
  E.g. scheduling (at 6pm server time) a raid for 9pm server would assume 9pm had already passed and schedule it for tomorrow 9pm instead of today 9pm.

QoL:

• Scheduling a raid for more than one week in advance is now allowed: It no longer errors, but instead provides a warning to check if the date parsed correctly.

3.5 first patch

Bugfixes:
-You can once again assign a player to the first slot.

Features:
-The shorthand command no longer requires the channel name to specify the tier, but defaults to T1 instead.
-You can now update the raid tier when clicking on settings.

Backend improvements

Only backend improvements this version.
-Logging messages are now written to a log file instead of stdout.
-Raid data is now stored in a sqlite database instead of saved to disk as a file every time something changes. This should reduce resource usage. (It will also allow you to update the raid data directly in the database, should you wish.)

This version will not be able to read raid data files generated by version 3.4 or lower, so only update if you have no raids scheduled.

QoL update

-The first time you sign up with a new class you will now automatically get assigned that class role.
This change allows users to sign up with the green check mark without having to manually assign themselves the roles by clicking the class emoji on the role post. Removal of class roles is still exclusively done via the role post.
-The displayed time zones in raid posts are now configurable.
You will need to update your config file, version 3.4.0 will not work with old config files. The examples have been updated accordingly.

Bugfix

The background task crashed when a raid was starting.

No code changes.

Fixed the requirements.txt file.
Edited the README.

Major Patch

New features:
-When selecting your raid lineup the bot will now update the raid post in (almost) real time. Timeout on selecting your raid lineup has been increased from 20s to 60s.
-The bot command prefix can (and must) now be specified in the config file.
-The default class lineup for raid can (and must) now be specified in the config file.
-The about command now pulls the latest version info from Github.

Things will break if you do not update your config file, there is no fallback.
The example config file has been updated, so you can simply copy that and put your bot token in if you were using the default settings.
N.B. The file list-of-raids has also had its format changed, but this should only matter if you were using a custom one.
You'll also need to install the requests module if you don't have it yet.

Bug fix:
-The background task now gets properly killed when you reload the code on a live bot so you do not end up with two copies running simultaneously.

Major Patch

New features:
-When selecting your raid lineup the bot will now update the raid post in (almost) real time. Timeout on selecting your raid lineup has been increased from 20s to 60s.
-The bot command prefix can (and must) now be specified in the config file.
-The default class lineup for raid can (and must) now be specified in the config file.

Things will break if you do not update your config file, there is no fallback.
The example config file has been updated, so you can simply copy that and put your bot token in if you were using the default settings.

Bug fix:
-The background task now gets properly killed when you reload the code on a live bot so you do not end up with two copies running simultaneously.

Miscellaneous:
Some code optimization that you probably won't notice, unless it introduced new bugs. Hence releasing as a beta for now.