This is the first part of the fixes for MDEV-24097. This commit
contains the fixes for instability when testing Galera and when
restarting nodes quickly:

1) Protection against a "stuck" old SST process during the execution
   of the new SST (after restarting the node) is now implemented for
   mariabackup / xtrabackup, which should help to avoid almost all
   conflicts due to the use of the same ports - both during testing
   with mtr, so and when restarting nodes quickly in a production
   environment.
2) Added more protection to scripts against unexpected return of
   the rc != 0 (in the commands for deleting temporary files, etc).
3) Added protection against unexpected crashes during binlog transfer
   (in SST scripts for rsync).
4) Spaces and some special characters in binlog filenames shouldn't
   be a problem now (at the script level).
5) Daemon process termination tracking has been made more robust
   against crashes due to unexpected termination of the previous SST
   process while new scripts are running.
6) Reading ssl encryption parameters has been moved from specific
   SST scripts to a common wsrep_sst_common.sh script, which allows
   unified error handling, unified diagnostics and simplifies script
   revisions in the future.
7) Improved diagnostics of errors related to the use of openssl.
8) Corrections have been made for xtrabackup-v2 (both in tests and in
   the script code) that restore the work of xtrabackup with updated
   versions of innodb.
9) Fixed some tests for galera_3nodes, although the complete solution
   for the problem of starting three nodes at the same time on fast
   machines will be done in a separate commit.

No additional tests are required as this commit fixes problems with
existing tests.