Upload bootnode info & use in docs instead of static nodes

[tkporter]

Description

This uploads a file to GCS containing the enode URL of the bootnode upon deploying a network, and has users use the bootnode to discover other nodes in the docs for the proxy and attestation service nodes.

Seeing as the node run locally is temporary, I kept that using static nodes. This avoids polluting the bootnode discovery table & also ensures quick peer connections. I'm open to changing this though

Tested

Ran it myself and was able to find nodes through the bootnode

Other changes

Cleaned up a little code and fixed a couple small nits in the docs

Related issues

Partner PR in blockchain: celo-org/celo-blockchain#769

Backwards compatibility

Requires a new version of celo-node resulting from this PR: celo-org/celo-blockchain#769

[codecov]

Codecov Report

Merging #2289 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2289   +/-   ##
=======================================
  Coverage   74.89%   74.89%           
=======================================
  Files         274      274           
  Lines        7803     7803           
  Branches      701      701           
=======================================
  Hits         5844     5844           
  Misses       1846     1846           
  Partials      113      113

Flag	Coverage Δ
#mobile	74.89% <ø> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e599ef8...408b3b4. Read the comment docs.