Proposals: increase limit of funding proposals

## Problem
Currently, spending/funding proposals have a limit of 166k which makes them quite limited for certain uses. This means that governance is sometimes bypassing this by using WG budgets.

## Solution
* Increase limit from 166k to at least 1 million $JOY
* Consider increasing approval requirement to 100% because it seems unlikely that spending proposals are ever really going to be used for small amounts--all smaller funding has almost always gone through WGs
* The stake required should also be increased--it is currently only 166 $JOY which is a very low amount!