jetbrains-gateway in air-gapped environment can't download the backend

[Heshmatkhah]

Hi
In addition to #22,

When you use JetBrains Client Downloader to clone required IDEs into your air-gapped environment, It will create/update a /products.json file witch contains all required information of your mirror, including

• build number
• version
• download link

But, The module hardcoded the download link of each IDE instead of getting current the releases_base_link/products.json

Also the version info is downloaded from {releases_base_link}/products/releases instead of {releases_base_link}/products.json and that endpoint is only available on official mirror.

Potential fix:

Use {releases_base_link}/products.json to get release information.

When you are generating effective_jetbrains_ide_versions from jetbrains_ide_versions, save the .releases[{INDEX}].downloads[{INDEX_2}].{PLATFORM}.link and use that with the download_base_link!

In most air-gapped environments, the download_base_link and releases_base_link should be the same.