Add remaining Otel (0.7.0) semantic attributes

[slashmo]

This PR is part of the effort to be on par with Otel 0.7.0 (#32). It adds the remaining semantic span attributes and updates existing ones. All documentation comments pointing towards Otel have been updated to point to the specific 0.7.0 version on GitHub.

[slashmo]

@ktoso / @tomerd: I'm not sure why the CI is failing here, seems to be something wrong with Jenkins:

java.io.FileNotFoundException: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.275.b01-0.el7_9.x86_64/jre/lib/currency.data (No such file or directory)

[ktoso]

@swift-server-bot test this please

[ktoso]

LGTM, thanks!

Can you mass change the - See to - SeeAlso and merge? 👍

CI just had some hiccups, builds ok now :-)

[ktoso]

Does this completely resolve #32 or still some things to check?

[slashmo]

Does this completely resolve #32 or still some things to check?
@ktoso

I think it depends on whether we want to add some kind of Resource (#39). If so, I'd include it in #32 as well. Otherwise, I'd have to look through the spec once more but I think we're already on par with Otel 0.7.0.