config: deprecate LabelType and CheckLabels

[alaaeddineelamri]

Description

This PR adds deprecates LabelType and CheckLabels.
We initially only wanted to deprecate ANSI/IBM labels, but since deprecating/removing them would make the Bareos label the default anyway, just removing the whole config option makes sense.

Please check

• Short description and the purpose of this PR is present above this paragraph
• Your name is present in the AUTHORS file (optional)

If you have any questions or problems, please give a comment in the PR.

Helpful documentation and best practices

• Git Workflow
• Automatic Sourcecode Formatting
• Check your commit messages
• Boy Scout Rule

Checklist for the reviewer of the PR (will be processed by the Bareos team)

Make sure you check/merge the PR using devtools/pr-tool to have some simple automated checks run and a proper changelog record added.

General

• Is the PR title usable as CHANGELOG entry?
• Purpose of the PR is understood
• Commit descriptions are understandable and well formatted
• Check backport line
• Required backport PRs have been created

Source code quality

• Source code changes are understandable
• Variable and function names are meaningful
• Code comments are correct (logically and spelling)
• Required documentation changes are present and part of the PR

[pstorz]

Wouldn't it be simpler to set the configuration directive itself to deprecated:

diff --git a/core/src/stored/stored_conf.cc b/core/src/stored/stored_conf.cc
index 173aeef20..ce04c58a3 100644
--- a/core/src/stored/stored_conf.cc
+++ b/core/src/stored/stored_conf.cc
@@ -198,7 +198,7 @@ static ResourceItem dev_items[] = {
   {"MountPoint", CFG_TYPE_STRNAME, ITEM(res_dev, mount_point), 0, 0, NULL, NULL, NULL},
   {"MountCommand", CFG_TYPE_STRNAME, ITEM(res_dev, mount_command), 0, 0, NULL, NULL, NULL},
   {"UnmountCommand", CFG_TYPE_STRNAME, ITEM(res_dev, unmount_command), 0, 0, NULL, NULL, NULL},
-  {"LabelType", CFG_TYPE_LABEL, ITEM(res_dev, label_type), 0, 0, NULL, NULL, NULL},
+   {"LabelType", CFG_TYPE_LABEL, ITEM(res_dev, label_type), 0, CFG_ITEM_DEPRECATED, NULL, "-23.0.0", NULL},

This creates a deprecation warning like this:

here are configuration warnings:
 * using deprecated keyword LabelType on line 14 of file .../etc/bareos/bareos-sd.d/device/FileStorage.conf

Also, we probably need to update the documentation about the tape labels, see: https://docs.bareos.org/Appendix/Troubleshooting.html#tape-labels-ansi-or-ibm

Additionally, we probably want to deprecate also the directive CheckLabels. as it seems only to be used for IBM/ANSI Labels