Explicitly enable meson features in CI

Hi,

Right now, many features are set to auto in Meson builds in CI. This
means Meson tries to detect these features automatically but does not
report an error if it fails to find them. Jacob stated [1] that this
behavior can lead to issues, such as missing problems in the build
system. Additionally, since CI images are updated automatically, an
update could cause a feature to go missing without any warning.
Therefore, Jacob suggested explicitly enabling these features in the
Meson build configuration. The attached patch implements this change.

I manually checked features from the end of the 'meson setup'
command's output in each task and stored these enabled features in the
MESON_FEATURES variable. I think this should be enough but of course
an automated way would be better if there is any.

One thing I’m unsure about the patch is that all these features are
stored in the MESON_FEATURES environment variable in each task. I
wonder if it might be clearer to rename these variables to
${TASK_NAME}_MESON_FEATURES to avoid confusion.

Also, libcurl is disabled in the OpenBSD CI task until the fix in this
thread [1] is committed.

Any feedback would be appreciated.

[1] https://www.postgresql.org/message-id/CAOYmi%2BkdR218ke2zu74oTJvzYJcqV1MN5%3DmGAPqZQuc79HMSVA%40mail.gmail.com

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Regards,
Nazir Bilal Yavuz
Microsoft