Add news to website

Description

As a user and also as a developer, I want to know/to emphasize the latest important developments about DBnomics.

For instance, the WEO:latest change is really important but only appears on the forum (see email from A. Vester today).

DBnomics forum will be used to write and store news in a dedicated dbnomics-news category.

To avoid duplicating the places to read content from, there will be a link from the website nav-bar to the dbnomics-news category of the forum. We will not add a news page on the website with dedicated Markdown content, like the about page (cf #490 (closed)).

Also, latest news should appear on the home page. This means that a dedicated section of the home page will display the N latest posts of the dbnomics-news category. The number of latest posts will be configured.

Technical notes

• add a new NB_HOMEPAGE_NEWS environment variable with a default value of 3
• add a new FORUM_NEWS_CATEGORY environment variable with a default value of dbnomics-news
• add a new FORUM_URL environment variable with a default value of null
• add a new FORUM_API_URL environment variable with a default value of null

Tasks

• Create dbnomics-news category
• Move the previous post on latest releases in this category
• Add a link in the nav-bar to the dbnomics-news category
• If the homepage, request the forum API to fetch the NB_HOMEPAGE_NEWS latest news from the FORUM_API_URL