Rename *FunctionFormulaType to *UninterpretedFunctionDeclaration.
The old name was confusing because the FunctionFormulaType was not
related to FormulaType.

git-svn-id: https://svn.sosy-lab.org/software/cpachecker/trunk@14683 4712c6d2-40bb-43ae-aa4b-fec3f1bdfe4c