static files stored in resources/ need an update

As it is known, investpy uses static data stored in CSV files in the resources/ directory, which was generated more than 3 months ago. And, since some static data related errors have been reported the past months, this files will be generated again and included in the next release.

These files do not change usually, since the data they contain is the indexed data in Investing.com, but some may suffer eventual updates. So on, their update frequency is estimated to be once a month, since they take too long to generate due to Investing.com request limiter.

Additionally, note that the financial products count in the README.md should be also updated since the count may change.

Also take into account that the financial product country files were previously turned into constants so as to avoid the load of unnecessary files as stated in #125 which is still under development. This means that the resources/ directory contents and structure may change.

alvarobartt / investpy

static files stored in resources/ need an update #134