Merge topic 'ExternalProject-TLS_VERSION'

2ef3bd9186 ExternalProject: Add TLS version options for https connections
f0a36b1a76 ExternalProject: Factor out helper to get NETRC options
019960a52a ExternalProject: Factor out helper to get TLS_CAINFO option
1afa6f359e ExternalProject: Factor out helper to get TLS_VERIFY option
e39c37ab29 ExternalProject: Revise wording of TLS_VERIFY documentation
fe5e6c27bd ExternalProject: Prepare for multiple git submodule config options

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Acked-by: Craig Scott <craig.scott@crascit.com>
Merge-request: !9296