[receiver/hostmetrics] Remove system.linux.memory.available metric

[rogercoll]

Component(s)

receiver/hostmetrics/internal/scraper/memoryscraper

Is your feature request related to a problem? Please describe.

Since open-telemetry/semantic-conventions#2534 and #42223, system.linux.memory.available metric can be derived from system.memory.limit - system.memory.usage{state=used}

Describe the solution you'd like

Should we remove/deprecate this metric?

Describe alternatives you've considered

No response

Additional context

No response

Tip

_{React with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding +1 or me too, to help us triage it. Learn more here.}

[github-actions]

Pinging code owners:

• receiver/hostmetrics: @dmitryax @braydonk

See Adding Labels via Comments if you do not have permissions to add labels yourself.