Remove most doxygen file-level commands, copyrights, and authors

Remove the \file directive, as it is always superfluous  because the
current file is implicit [1]:

> If the file name is omitted (i.e. the line after \file is left blank)
> then the documentation block that contains the \file command will belong
> to the file it is located in.

Author names and e-mails are not relevant for us: it can always be
inferred from git blame, and is often outdated.

Eurecom code has been contributed and was under OAI PL v1.0/v1.1.

For the cpack package contact: put generic email address that is
independent of an individual and that will remain reachable.

[1] https://www.doxygen.nl/manual/commands.html#cmdfile

targets/TEST/PDCP/readme.txt

@@ -19,13 +19,6 @@
  *      contact@openairinterface.org
  */
 
-/*________________________OEPNAIR/OPENAIR0/________________________
-
- File    : readme.txt 
- Authors : Baris Demiray
- Company : EURECOM
- Emails  : baris.demiray@eurecom.fr
-________________________________________________________________*/
 
 
 -----------------

targets/TEST/PDCP/test_pdcp.c

@@ -21,8 +21,6 @@
 
 /*
  * PDCP test code
- *
- * Author: Baris Demiray <baris.demiray@eurecom.fr>
  */
 
 #include "MAC_INTERFACE/vars.h"

targets/TEST/PDCP/test_pdcp.h

@@ -21,8 +21,6 @@
 
 /*
  * PDCP test code
- *
- * Author: Baris Demiray <baris.demiray@eurecom.fr>
  */
 
 #ifndef TEST_PDCP_H

targets/TEST/PDCP/test_util.h

@@ -22,8 +22,6 @@
 
 /*
  * Helper methods for PDCP test code
- *
- * Author: Baris Demiray <baris.demiray@eurecom.fr>
  */
 
 #ifndef TEST_UTIL_H

targets/TEST/PDCP/todo.txt

@@ -2,6 +2,3 @@
 * Test configuration should be configurable on run-time (command-line?)
 * Inbetween every test PDCP entity should be reinitialized or different 
   PDCP entities should be utilised
-
-
-baris.demiray@eurecom.fr