chore(measure_theory): move and rename some lemmas (#12699)
* move `ae_interval_oc_iff`, `ae_measurable_interval_oc_iff`, and `ae_interval_oc_iff'` to `measure_theory.measure.measure_space`, rename `ae_interval_oc_iff'` to `ae_restrict_interval_oc_iff`;
* add lemmas about `ae` and union of sets.
