Create Subduction PlausibilityFilter to guarantee connectedness

[voj]

We have encountered a disconnected subduction rupture in a test build, and we would like to

• check if we have any disconnected ruptures in the NZSHM22 subduction rupture sets
• prevent this from happening during future rupture set generation.

We currently generate subduction ruptures as rectangles, but we allow for missing tiles because the edges of subduction tile sets are usually ragged. We have plausibility filters in place to guarantee

• that the aspect ratio is rectangular
• that there are not too many missing tiles

We should add a new PlausibilityFilter to guarantee that all sections in a rupture are connected and that there are no "islands".

This rupture was generated using SBD_0_1_PUY_30:

input	value
min_aspect_ratio	2.0
max_aspect_ratio	5.0
aspect_depth_threshold	5
min_fill_ratio	0.1
growth_position_epsilon	0.0
growth_size_epsilon	0.0