FTBFS with dependencies versions in focal

[Evan Caville]

When building rainloop1.12.1 from source, multiple errors are encountered, deriving from limitations in dependency packages and their versions. The first encountered is:

The following packages have unmet dependencies:
 builddeps:rainloop : Depends: node-jquery (< 3.0.0) but it is not going to be installed

Applying the following commit overcomes this:
https://salsa.debian.org/js-team/rainloop/-/commit/8d860ddd4af637c9f32cf87c737867747079350d

However, the next FTBFS errors encountered are seen in the attached `FTBFS1_rainloop_1.12.1-2ubuntu0.1_amd.build` and applying the following updates to the debian-libraries.patch file handles some of these errors:
https://salsa.debian.org/js-team/rainloop/-/commit/43f07434c0135558e3593b0f3ef7ab894915a9dc

What is left is the core-js related build errors seen in the attached `FTBFS2_rainloop_1.12.1-2ubuntu0.1_amd.build`. This looks to be caused from some dependent nodejs packages being upgraded/updated whilst the webpack & babel packages and plugins available in focal remain at a version incompatible with the core-js needed to successfully build rainloop1.12-1. Meaning this package remains with FTBFS errors.