[New model] Add Mase1989

[chrisleaman]

Who is the published the model and in what year?
Mase (1989)

Please provide a link, doi or citation to the paper
Mase, H., 1989. Random Wave Runup Height on Gentle Slope. Journal of Waterway, Port, Coastal, and Ocean Engineering 115, 649–661. https://doi.org/10.1061/(ASCE)0733-950X(1989)115:5(649)

If possible, please provide the relevant equation references
For example:

• Eqn 5 with a=1.86, b=07.1: R2

Any other details that would be useful?
For example:

• Data derived from small-medium sized wave flume on planar impermeable slope