Refactoring hcl specifications

[jeroenrinzema]

The HCL specification parser contains a lot of code duplications. Interfaces should be created to simplify the parsing of intermediate HCL files. The following functions could most likely be simplified:

ParseIntermediateInputParameterMap
ParseIntermediateNestedParameterMap
ParseIntermediateRepeatedParameterMap
ParseIntermediateCallParameterMap
ParseIntermediateParameterMap

semaphore/pkg/providers/hcl/specs.go

Lines 16 to 20 in 7889d18

	/**
	* TODO: this file has to be refactored to avoid code duplication and
	* type casting. A lot of code duplication is aroundnested and repeated parameter
	* maps. Interfaces have to be created for these types to allow to reuse implementations.
	*/