Deprecate 'openwebxchange' bidder page (use 'openweb')

[liranm-creator]

This PR marks the 'openwebxchange' bidder as deprecated. It has been replaced by the maintained 'openweb' bidder, which supports Prebid Server and current configurations. Submitted by Liran (OpenWeb monetization team).

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[muuki88]

I would also recommend putting a warning in the bidder documentation at the top.

[liranm-creator]

I would also recommend putting a warning in the bidder documentation at the top.

Thanks for the feedback, I’ve added the deprecation warning at the top of the bidder documentation as recommended. Please LMK if anything else is wrong or missing.

[muuki88]

I would also recommend putting a warning in the bidder documentation at the top.

I see that this was a bit misleading 😅 I meant not at the top of the meta data, but the actual human readable part. Directly under the Notes heading.

This is how you format it nicely

### Notes

{: .alert.alert-warning :}
Deprecated!!

...