MDEV-21303 Make executables MariaDB named

To change all executables to have a mariadb name I had to:
- Do name changes in every CMakeLists.txt that produces executables
- CREATE_MARIADB_SYMLINK was removed and GET_SYMLINK added by Wlad to reuse the function in other places also
- The scripts/CMakeLists.txt could make use of GET_SYMLINK instead of introducing redundant code, but I thought I'll leave that for next release
- A lot of changes to debian/.install and debian/.links files due to swapping of real executable and symlink. I did not however change the name of the manpages, so the real name is still mysql there and mariadb are symlinks.
- The Windows part needed a change now when we made the executables mariadb -named. MSI (and ZIP) do not support symlinks and to not break backward compatibility we had to include mysql named binaries also. Done by Wlad

extra/mariabackup/CMakeLists.txt

@@ -55,7 +55,7 @@ ENDIF()
 
 ADD_DEFINITIONS(-DPCRE_STATIC=1)
 ADD_DEFINITIONS(${SSL_DEFINES})
-MYSQL_ADD_EXECUTABLE(mariabackup
+MYSQL_ADD_EXECUTABLE(mariadb-backup
   xtrabackup.cc
   innobackupex.cc
   changed_page_bitmap.cc
@@ -82,17 +82,13 @@ MYSQL_ADD_EXECUTABLE(mariabackup
   COMPONENT backup
   )
 
-
-
-
 # Export all symbols on Unix, for better crash callstacks
-SET_TARGET_PROPERTIES(mariabackup PROPERTIES ENABLE_EXPORTS TRUE)
+SET_TARGET_PROPERTIES(mariadb-backup PROPERTIES ENABLE_EXPORTS TRUE)
 ADD_SUBDIRECTORY(crc)
 
-
-TARGET_LINK_LIBRARIES(mariabackup sql sql_builtins crc)
+TARGET_LINK_LIBRARIES(mariadb-backup sql sql_builtins crc)
 IF(NOT HAVE_SYSTEM_REGEX)
-  TARGET_LINK_LIBRARIES(mariabackup pcre2-posix)
+  TARGET_LINK_LIBRARIES(mariadb-backup pcre2-posix)
 ENDIF()