Create an API method to remove cached zip files for a given data package

[servilla]

Currently, when a user requests a data package archive zip file, PASTA first checks to see if a cached version of the zip archive file exists in the archive cache directory. If a cached version of the zip archive file exists, PASTA will return it rather than creating a new zip (which may be time-consuming if consisting of many or large data entity files). These cached versions of zip archive files persist until manually removed. Unfortunately, the advent of setting data entity embargos post-creation of the data package has introduced the possibility of embargoed data being exposed in a pre-embargo-created zip archive file (see #77). For this reason, an API method to remove all zip files from the archive cache directory is necessary.

This API method should support the following:

1. The owner of the data package should be allowed to execute this method.
2. PASTA administrators (TBD) should be allowed to execute this method.
3. This method should be idempotent.