Replace usage of brok with blc or equivelant npm package

[Derek Ardolf]

GitHub doesn't like all the calls that brok is doing against it, and brok doesn't have much support for customizing output around particular status returns. I'm going to add it to .brokignore for now so that this PR passes without the 429 failures, as I'd like to suppress 429 failures since they aren't the same as 404, etc.

I'm going to make a follow-up issue that could enhance the URL validator approach, in the future, with some starter commands that I'd have to experiment with at a later date. This approach would allow for internal links as well as external links, and would ensure that the site can build without errors. It seemed like using blc, or other npm based tool would be more forward thinking in case anything like dendron-cli would be extended to make use of the package (or similar package).

# container
# node:14-bullseye-slim
npm install broken-link-checker
npm install serve
npm install @dendronhq/dendron-cli@latest
npm install @dendronhq/dendron-11ty@latest
npx dendron-cli buildSiteV2 --wsRoot .  --stage prod
npx serve 2>> /dev/null &
blc http://localhost:5000/notes -ro --exclude-internal > output-internal.log
blc http://localhost:5000/notes -ro --exclude-external > output-external.log

Originally posted by @ScriptAutomate in #179 (comment)