.gitmodules: switch away from repo.or.cz

.gitmodules: switch away from repo.or.cz

The host repo.or.cz is often offline, creating issues for cloning
and building OpenOCD from scratch.
Already 'jimtcl' developer has dropped repo.or.cz, triggering the
OpenOCD commit 861e75f54efb ("jimtcl: switch to github").

Change also the link of the remaining submodules 'git2cl' and
'libjaylink' to their respective main repository.

Change-Id: Ib513237427635359ce36a480a8f2060e2fb12ba4
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/6834
Tested-by: jenkins
Reviewed-by: zapb <dev@zapb.de>