Move my-icpc-reactions scripts into cds-convertor publisher

[lperovskaya]

cc https://github.com/icpc/my-icpc-reactions

reactions website needs two files to display the list of submissions and media reaction links:
contestInfo.json and runs.json
https://news.icpc.global/reactions/2024/data/contestInfo.json

• is like normal contestInfo with the added extra field of
  "reactionsUrlTemplate":"https://d1x79igug69x01.cloudfront.net/wf/2024/reactions/reaction-$.mp4"}

https://news.icpc.global/reactions/2024/data/runs.json

• is currently like normal concatenated externalRun, but with the added extra field of "reactionUploaded": true
• don't add "reactionsUploaded" to the export, it will need to be moved into a separate file to keep the architecture clean.

• Add custom fields to a contest. Move reactionsUrlTemplate there
• support contestInfo.json and runs.json export files in publisher mode
• support ftp upload with user and password (test on bluehost)

after that

• Lidia to update reactions frontend code to take the list of uploaded reactions from a separate file doneReactions.json
• first to solve emoji
• filter by first to solve in verdicts
• use doneReactions.json in reactions frontend instead of runs.json
• when available rankAfter in runs.json -> add first position emoji
• update reactions-generator to use external run from convertor
• change reactionurltemplate variable in code of frontend
• move all past reactions archives to new json format + update frontend
• add new filters First-to-solve and First-place