Adds xhr connection managment to http/1.1 installs
This includes various things:
1. An object pool to 'acquire', 'release' and 'dispose' of objects, also
a 'purge' to completely empty it
2. A `Request` data object, mainly for reasoning about the object better
3. A pseudo http 'client' which doens't actually control the request
itself but does help to manage the connections
An initializer is used to detect the script element of the consul-ui sourcecode
which we use later to sniff the protocol that we are most likely using for API access
In some circumstances a consul 1.4 client could be running in an
un-upgraded 1.3 or lower cluster. Currently this gives a 500 error on
the new ACL token endpoint. Here we catch this specific 500 error/message
and set the users AccessorID to null. Elsewhere in the frontend we use
this fact (AccessorID being null) to decide whether to present the
legacy or the new ACL UI to the user.
Also:
- Re-adds in most of the old style ACL acceptance tests, now that we are keeping the old style UI
- Restricts code editors to HCL only mode for all `Rules` editing (legacy/'half legacy'/new style)
- Adds a [Stop using] button to the old style ACL rows so its possible to logout.
- Updates copy and documentation links for the upgrade notices
John Cowen