Add collectives and glutton parachain westend runtimes to prepare for
#1737.

The removal of system parachain native runtimes #1737 is blocked until
chainspecs and runtime APIs can be dealt with cleanly (merge of #1256
and follow up PRs).

In the meantime, these additions are ready to be merged to `master`, so
I have separated them out into this PR.

Also marked `bridge-hub-westend` as unimplemented in line with [this
issue](https://github.com/paritytech/parity-bridges-common/issues/2602).

TODO
- [x] add to `command-bot` benchmarks
- [x] add to `command-bot-scripts` benchmarks
- [x] generate weights

---------

Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>
Co-authored-by: Muharem <ismailov.m.h@gmail.com>
Co-authored-by: command-bot <>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Branislav Kontur <bkontur@gmail.com>