Allow templates for downloaded files

[thibaultamartin]

Atm the names of the files downloaded with the curl command are quite cryptic.
Templatifying the names of the downloads would be great. The following variables make sense imho:

• yyyy year in 4 digits format
• mm month of the year
• dd day of the month
• section name of the section in which the related news is in (if any, nosection if in none), kebab cased
• project name of the project to which the related news is in (if any, noproject if in none), kebab cased

In case of duplicate name, appending a -n with n being an integer should do the trick

An example of template for the downloads could be: {{ yyyy }}-{{ mm }-{{ dd }}-twim-{{ section }}-{{ project }}
The resulting downloaded file would be:

• 2022-10-14-twim-clients-element-ios.png
• 2022-10-14-twim-clients-element-ios-1.png
• 2022-10-14-twim-servers-noproject.jpg