[C++] Flag const_cast usage when linting

### Describe the enhancement requested

`const_cast` usage sometimes goes unnoticed when reviewing (it has crept up in the Parquet encryption code, for example).

We should explicitly flag it during linting, so that `const_cast` has to be explicitly allowed where required.

### Component(s)

C++

Start by locating Apache Arrow's C++ lint configuration and inspect the Parquet encryption code mentioned in the issue for existing const_cast usage. Run the relevant lint checks to understand current behavior; done means const_cast is flagged and any required uses are explicitly allowed.

Written by the indexing model from the issue text.