Remove support for depreciated modules

Problem/Motivation

The Profile module was part of core in Drupal 6, but was depreciated in Drupal 7.
The Content module was part of the CCK project in Drupal 5, but does not exist in Drupal 6 and Drupal 7.
The contributed Publication and Schedule projects has a Drupal 6 releases, but there no release Drupal 7.

For Drupal 7, there are two options that can be used instead of Profile and Content:

1. Use Fields now provided by core (replacement for CCK) to add profile fields to the user profile.
2. Use the Profile 2 module (re: #1957556: Make User Import support Importing into Profile2 Fields for D7)

Since there are no module named "profile" in Drupal 7, this statement in profile.inc:

if ($module != 'profile') return;

will always be TRUE and there is not much point in having profile.inc in the repo.

Since there are no module named "content" in Drupal 7, these statement in content_profile.inc and subscribed.inc:

if (module_exists('node_import') && module_exists('content'))
if (module_exists('publication') && module_exists('schedule')) {

will never be TRUE and there is not much point in having content_profile.inc or subscribed.incin the repo.

Also, all open issues that are about these depreciated modules are just noise in the issue queue.

Proposed resolution

Clean up everything related to the depreciated modules from the issue queue and the code.

Remaining tasks

None.

The following has neen done:

1. Identify all issues that are about the depreciated modules and flag them as child issues of this one.
2. Close all those issues as outdated.
3. Delete profile.inc from the project.
4. Delete content_profile.inc from the project.
5. Delete subscribed.inc from the project.
6. Delete any other code are there to support these modules.