Fixed reading of time variable wave data in yaml input

[wilfchun]

This pull request introduces support for configuring wave input modes in the simulation, allowing users to specify whether wave data should come from a fixed value or a time series. It also improves YAML parsing flexibility for raster files and fixes a bug in cliff collapse configuration. The most important changes are grouped below:

Wave Input Mode Configuration

• Added a new member m_strWaveInputMode to CConfiguration, with corresponding getter and setter methods, and initialized its default value to "fixed". [1] [2] [3] [4]
• Updated YAML configuration parsing to read a new wave_input_mode parameter, and conditionally load wave data as either fixed values or from time series files based on this mode. If an unknown mode is supplied, an error is reported. [1] [2]
• Modified application of configuration to use the appropriate wave data source depending on the selected mode.

YAML Parsing Improvements

• Updated raster files parsing to accept both a list and a single file entry in the YAML configuration, improving user flexibility.

Bug Fix

• Fixed an assignment bug in the cliff collapse configuration by correctly setting m_bDoCliffCollapse instead of overwriting m_dDeanProfileStartAboveSWL.