Event based lift / door logic

[luca-della-vedova]

New feature implementation

Implemented feature

Part of open-rmf/rmf_simulation#114.

Implementation description

This PR performs a few small changes in how we interact with infrastructure:

• For doors and lifts, increase our queue size (previously used system default that has a queue size of 1) and explicitly mark it reliable.
• For lifts, make sure that we publish a message immediately when a request from a fleet adapter is received. Previously the request was only saved and sent the next time a lift update was received. This should make latency when operating lifts slightly better.
• Similarly for fleet adapters, release the lift as soon as needed, previously the release was also done in a lift state callback.

[luca-della-vedova]

This should be ready for review.

It shouldn't be too controversial and these should be strictly improvements in the latency of the system, what will be more controversial instead is the changes on the rmf_simulation side that change the publishing method to be event based, so I'll make sure to test those more extensively.

[mxgrey]

I've tested this out, no problems at all. It should be a pure upgrade to how messages are currently handled, and fully backwards compatible 👍