Improve object filtering

The try/except clause at the start of our `home` method was insufficient. The last .get would frequently return multiple objects. In the most recent test, it did so in ~8% of cases.

This can be simplified by using filters and ordering by action_type.

I also put a check in place in the `micrositetag` method which prevents it from trying to run manipulations multiple times, potentially leading to an infinite loop.

All tests pass.