Adjust links in docs to not include tracker

[consideRatio]

There is a pending question about this in a PR, but I think we should avoid waiting for that to merge, so I opened this issue to offload this from the PR

Current documentation in docs/install/azure.rst:

• To get started you can get a free account which includes 150 dollars worth of Azure credits (get a free account here <https://azure.microsoft.com/en-us/free//?wt.mc_id=TLJH-github-taallard>_)

@manics write:

Do we need the ?wt.mc_id=TLJH-github-taallard (tracking?) identifier here and in the other Azure links?

@minrk wrote:

I'm not sure, @trallard can you comment on the campaign ID in the azure links (added in https://github.com/jupyterhub/the-littlest-jupyterhub/pull/342)?

[trallard]

Ah those can be removed for sure. I am on PTO so not spending a lot of time around here until next week in case you need a review or anything