Several fixes to make code compile and linter not complain

.eslintrc.json

package.json

src/ast/Node.ts

src/ast/Visitor.ts

src/ast/VoidVisitor.ts

src/ast/declarations/ConditionDeclaration.ts

src/ast/declarations/MainAgent.ts

src/ast/declarations/Monitor.ts

src/ast/declarations/ProcedureDeclaration.ts

src/ast/declarations/ProcedureParameter.ts

src/ast/declarations/Program.ts

src/ast/declarations/Struct.ts

src/ast/declarations/VariableDeclarations.ts

src/ast/declarations/VariableDeclarator.ts

src/ast/declarations/VariableInitializer.ts

src/ast/declarations/index.ts

src/ast/expressions/AdditiveExpression.ts

src/ast/expressions/AndExpression.ts

src/ast/expressions/ArrayExpression.ts

src/ast/expressions/AssignDestination.ts