Mastodon: Make the Getting Started column/menu movable

[Cassolotl]

From the toot with the idea in it:

I wish #mastodon allowed you to move the "Getting Started" pane left or right. If pin a new column with a hashtag you are interested in, the "Getting Started" pane moves further and further to the right.

I'd rather have it continuously visible, and the followed tags trailing off to the right.

This is the second person in two days who I've seen request this, so I think it should be here on the issue list!

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• [ ] I searched or browsed the repo’s other issues to ensure this is not a duplicate.
• [ ] This bug happens on a tagged release and not on master (If you're a user, don't worry about this).

[nailyk-fr]

Only to be more clear about what column we are talking about: https://github.com/tootsuite/mastodon/pull/3207 bring ability to pin lot of columns and that is really great.
However the 'multi purpose' column (the far-right variable column that appears for getting-started menu & searches) cannot be moved.
While creating more than 2 custom columns, even on full HD screens, this make Mastodon difficult to use because of constant horizontal scrolling. On smaller screens like laptop it almost prevent custom columns using.

P.S.: My instance is currently running the latest (2.0.0) release.

Many thanks.