Relax disconnect and cookies

[cjrace]

Brief overview of changes

Resolves #67 and resolves #68 by adding additional arguments to customise the disconnect message and the cookies panel.

Why are these changes being made?

To allow more flexibility for non-EES dashboards, and to relax an overly strict ID requirement for cookies pages.

Detailed description of changes

1. Remove RCurl as it takes time to run, and is overly strict for the checking we need (means we can drop a dependency too!)
2. Allow IDs other than navlistPanel to be used for the navigation tabset a cookies panel is within (before it could only be that, but we didn't document that anywhere)
3. Add a support_contact email address option, if a team wants to put their own email on the disconnect message
4. Add a custom_refresh option for where sites have bookmarking enabled and want the raw site URL to be the refreshed link

For example if the bookmarking or those specific options are what caused the error, reloading them exactly will just make it error again.

Additional information for reviewers

Some overlaps with #64 - I think there's clean up of the validation that can be done once that PR is in.

Issue ticket number/s and link

#67 and #68, both raised by Jake when making the LAIT dashboard.

[cjrace]

MacOS build was failing on the setup of R dependencies, so had to clear the cache entries for MacOS on this action and rerun - seems to work fine again now though not something I've seen before. Mentioning in case you hit it anywhere else next week @rmbielby