Feature request: Ability to download a specific (older) version of Firefox

[motin]

Older releases are available at https://ftp.mozilla.org/pub/firefox/releases/, and sometimes it is very handy to be able to download a specific older version of Firefox to be able to reproduce a certain bug found in an add-on or similar.

Example:

 $ bin/get-firefox -b release -v '59.0.2'
 $ bin/get-firefox -b esr -v 52

Also, sometimes Nightly is too unstable to run tests against, and being able to download nightly from a specific date would keep those CI jobs running without having to switch to testing against dev edition.

Example:

 $ bin/get-firefox -b nightly -t 20180730

I do understand that this is non-trivial since it would require a "ftp" container (or revival/fix of mozilla-get-url).

Also, there is a potential clash with the existing parameter:

  -v, --version                Version of the tool

[freaktechnik]

There already is a container for the FTP, but it's pretty broken currently, since it currently doesn't parse the HTML at all. It relied on a json file that always had the same name and contained the artifact files...

At least the nightly builds should be available via task cluster.