Add IQtree version with cmaple feature

[corneliusroemer]

Context

I've enabled the cmaple feature in bioconda's iqtree build.

Now what's stopping us from using it in nextstrain builds that are run in ci is lack of that feature in docker-base iqtree.

Binaries are available here: https://github.com/iqtree/iqtree2/releases/tag/v2.3.5.cmaple

Or one could just repackage the bioconda binaries directly - which would have the advantage of linux-aarch64 being available as well. This would solve #212

[corneliusroemer]

As I've mentioned in our Nextstrain zoom call: docker-base is what's holding us back from using iqtree's cmaple mode in workflows with CI. Cmaple mode means we get: a) better trees, b) faster, c) don't need to run a somewhat buggy fix-tree script.

Pinging a few who could be interested/helping here: @huddlej @victorlin @tsibley

[tsibley]

The change required here seems trivial? Trying it out in #228.

(Separately, iqtree2 calling the option that enables CMAPLE --pathogen is kinda weird, yeah?)

[tsibley]

#228 seems ok to me.