Add Stanage, Remove ShARC & Remove purchasing HPC info

[ptheywood]

• Adds references to Stanage where appropraite
• Removes references to ShARC from non-blog content where appropriate (Not all occurences replaced where unclear, i.e. NAG language page #719)
• Removes the very out of date HPC purchasing guide which is no-longer in line with current policy.

Closes #717

[ptheywood]

@willfurnass you don't have to review it, just wanted to make you aware the page was being murdered and that not mentioning purchasign hpc at all was the simpler option, rather than it going out of date again if policy changes.

[willfurnass]

LGTM. Suggest omitting mention of NAG on ShARC too.

[ptheywood]

LGTM. Suggest omitting mention of NAG on ShARC too.

I was going to leave the NAG/MAPLE links to deal with later, but yeah better to remove the refs for now and deal with if we want to keep the pages or not separately.

I've also removed the standard build on segments as suggested