Configurable timeout for API calls

[ianwdunlop]

OPs.js needs to have a configurable timeout for the API calls (see openphacts/ops.js#24). The explorer will need a timeout param in the config which can be picked up by the API calls it uses.

[jmartasek]

With a bit of hacking I managed to globally set the timeout by modifying vendor\assets\javascripts\combined.js (there is also one slightly different in public folder).

I added Constants.prototype.API_CALL_TIMEOUT = 60000; to the Constants definition and replaced all timeout: 30000 with timeout: new Constants().API_CALL_TIMEOUT

The value of the timeout can then be easily replaced with sed call in Dockerfile when building the image.