[sql] remove deprecated options and code

[ferdymercury]

This Pull request:

Changes or fixes:

Removes deprecated build options mysql odbc pgsql. It also does some cleanup of leftovers from the already deleted oracleoption.

@cern-sft-spi FYI

Checklist:

• tested changes locally
• updated the docs (if necessary)

[github-actions]

Test Results

    19 files      19 suites   3d 15h 41m 0s ⏱️
 2 745 tests  2 734 ✅ 0 💤 11 ❌
50 721 runs  50 710 ✅ 0 💤 11 ❌

For more details on these failures, see this check.

Results for commit f9e6946.

♻️ This comment has been updated with latest results.

[linev]

Plugin for TXNetFile can remain

Also all tutorials/io/sql can remain - they show usage of TSQLServer API
and can be useful for understanding how it can be used.
Even when examples refer to mysql or oracle DB.

[andresailer]

The LCGCMake recipes have been updated. Thanks for the heads-up!

[guitargeek]

@ferdymercury, please let us know when this PR is ready from your side so it can be merged.

[ferdymercury]

Thanks! It's ready now to "squash and merge" in my opinion, I have just added a mention to the 6.38 release note removal list.