NETSCRIPT: Add ramOverride() function (#1346)

This adds a way to dynamically change the static RAM limit of a script,
which is also its current RAM usage. This makes it possible for scripts
to dynamically change their memory footprint, opening up new strategies
beyond current ram-dodging.

Calling functions still permanently increases the *dynamic* memory
limit; RAM-dodging is still the optimal strategy for avoiding RAM costs,
in that sense.

This also adds dynamicRamUsage to the info returned by
`getRunningScript`, to allow introspection on the currently needed ram.

src/Netscript/RamCostGenerator.ts

@@ -569,6 +569,7 @@ export const RamCosts: RamCostTree<NSFull> = {
   getTotalScriptExpGain: RamCostConstants.GetScript,
   getScriptExpGain: RamCostConstants.GetScript,
   getRunningScript: RamCostConstants.GetRunningScript,
+  ramOverride: 0,
   formatNumber: 0,
   formatRam: 0,
   formatPercent: 0,