Systems deadlines countdown

Based on sec-deadlines by @clementfunt and ai-deadlines by @abshkdz

Adding/updating a conference

• Read the data format description below. Note that the timezone format sign is inverted (e.g., UTC+7 is written as Etc/GMT-7). It's not a bug. I hate this format too. I'd be happy to move to a different timezone JavaScript library that uses a friendlier format, but I don't have time for that.
• Update _data/conferences.yml. You can do that on Github or locally after forking the repo.
• Send a pull request

Conference entry record

Example record:

- name: NSDI
  description: USENIX Symposium on Networked Systems Design and Implementation
  year: 2022
  date: April 4-6
  comment: two deadlines; first abstract deadline March 4, second is Sep 9
  link: https://www.usenix.org/conference/nsdi22/call-for-papers
  timezone: Etc/GMT+8
  deadline: 
    - "2021-03-10 20:59"
    - "2021-09-15 20:59"
  place: Renton, Washington, USA
  tags: [NET]

Descriptions of the fields:

Field name	Description
name*	Short conference name, without year
year*	Year the conference is happening
description	Description, or long name
link*	URL to the conference home page
deadline*	Deadline, or list of deadlines. (Gory details below)
timezone	Timezone in tz format. By default is UTC-12 (AoE)
date	When the conference is happening
place	Where the conference is happening
tags	One or multiple tags: SEC, PRIV, or CRYPTO

Fields marked with asterisk (*) are required.

Deadline format

The deadline field can contain:

1. The simplest option: a date and time in ISO format. Example: "2017-08-19 23:59".
2. If a deadline is rolling, you can use a template date, just substitute the year with %y, or month with %m. Example: "%y-%m-15 23:59" means there is a deadline on the 15th day of every month, every year. "2017-%m-15" means a deadline on 15th day of every month, but only in 2017, i.e. "2018-01-15" is not a part of this template.
3. A list of (1) or (2). Example of two rolling deadlines, with one in the end of May every year, and the second in the end of February:

- "%y-05-31 23:59"
- "%y-02-28 23:59"

On the page, all deadlines are displayed in viewer's local time (that's a feature).

Note: If the deadline hour is {h}:00, it will be automatically translated into {h-1}:59:59 to avoid pain and confusion when it happens to be midnight in local time.

Timezones

The timezone is specified in tz format. Unlike abbreviations (e.g. EST), these are un-ambiguous. Here are tz codes for some common timezones:

Common name	tz
UTC	Etc/UTC
America Pacific Time	America/Los_Angeles
Pacific Standard Time (UTC-8)	Etc/GMT+8 (Yes, the sign is inverted for some weird reason)
America Eastern Time	America/New_York
Eastern Standard Time (UTC-5)	Etc/GMT+5
American Samoa Time (UTC-11)	Pacific/Samoa or Etc/GMT+11. This timezone does not use DST.
Aleutian Islands	America/Adak