runtime: reduce `council.minCandidateStake`

## Problem
There currently aren't enough people applying for the elections. The latest election only had 3 very late applicants which represents a security risk and also a long term risk to the project.
One of many reasons that this may be is that a user must have 166k $JOY in transferable tokens, which is not only a high amount but if the token price increases significantly more may present a significant barrier to new or even old users from applying.

## Solution
Reduce the minimum stake required to announce.
The current value is below:
`council.minCandidateStake: 1,666,666,666,660,000` (= 166666.6 $JOY)