Configurable MaxConcurrentReconciles with a better default for max-reconcile-rate

[turkenh]

Description of your changes

This PR:

• Uses --max-reconcile-rate for MaxConcurrentReconciles just like any other Crossplane providers rather than using a constant.
• Bumps the default for --max-reconcile-rate to 100. See the companion PR in provider kubernetes: https://github.com/crossplane-contrib/provider-kubernetes/pull/203
• Moves uptest for e2e testing (which was failing previously)

I have:

• [x] Read and followed Crossplane's [contribution process].
• [x] Run make reviewable to ensure this PR is ready for review.

How has this code been tested

See https://github.com/crossplane-contrib/provider-kubernetes/pull/203

[lsviben]

Looks ok but not sure why the e2e test is failing. Is it broken? Ill try to debug locally, but I see same thing is happening on master

[turkenh]

Looks ok but not sure why the e2e test is failing. Is it broken? Ill try to debug locally, but I see same thing is happening on master

@lsviben my other PR could be fixing it: https://github.com/crossplane-contrib/provider-helm/pull/197/commits/27b35cc5bbeece71c3c261de1e41d6e0e95591b9

Working on making it up to date as you suggested, then we can rebase this one.