This commit changes how the context is created and inherited to better
reflex the relationship of the components. We now have the following
context structure,
```
For ephemeral nodes, the context chain is,
main HarnessTest -> sub HarnessTest -> HarnessNode -> HarnessRPC
For standby nodes, the context chain is,
main HarnessTest -> standby HarnessNode -> HarnessRPC
```
This commit replaces the keys used in the maps `activeNodes` and
`standbyNodes` from `pubkeyStr` to `NodeID` such that even the node is
not properly started, we can still clean it up during shutdown.
In this commit, the bug demonstrated in the previous commit is fixed.
The locking capabilities of the AddressIterator are used to lock
addresses if they are being used for session negotiation. So now, when a
request comes through to remove a tower address then a check is first
done to ensure that the address is not currently in use. If it is not,
then the request can go through.
In this commit, a new test is added to demonstrate that an error is
thrown if a user attempts to remove a tower during session negotiation
even if no current negotiation is taking place with the tower.
This commit upgrades the wtclient package to make use of the new
`AddressIterator`. It does so by first creating new `Tower` and
`ClientSession` types. The new `Tower` type has an `AddressIterator`
instead of a list of addresses. The `ClientSession` type contains a
`Tower`.
In this commit, a new AddressIterator type is added. It is a type that
can be used to iterate over a list of addresses. It strictly disallows
the list of addresses it holds to be empty. It also allows callers to
place locks on certain addresses in order to prevent other callers from
removing the addresses in question from the iterator.
In this commit a helper method in ForwardingHistory is introduced that enriches
each ForwardingEvent by peer alias names for the incoming and outgoing channel.
In this commit, a test is added to demonstrate that if a client tries to
update the address of a tower for an active tower session, then this new
address will not be used until the client restarts. This is a bug that
will be fixed in a future commit.
This commit is a step towards prepping the watchtower client test
harness to be able to handle the case where the client connects to
multiple mock servers.
