Added rate rule for 1,3_Insertion_CO2 into a C-O bond in methoxymethane.

This comes from doi:10.1021/jp312643k
Details in the longDesc
Created a training entry for 1,3_Insertion_CO2 into methoxymethane.

This is defined in the direction that the original paper specified it.
The training program can find the reverse if it needs.

Rank unknown.
Valid Temperature range estimated.