List ftrack project on AYON server

[iLLiCiTiT]

Changelog Description

Implemented base of simple async ftrack session to collect ftrack projects using server, api key and username from ftrack settings.

Additional review information

Implemented ftrack session is using httpx which is available on server. The list of ftrack projects is available under endpoint /ftrackProjects.

Notes

I don't know what error code I should return when it is not possible to create ftrack connection, e.g. because missing/invalid ftrack url or missing/invalid credentials. Right now it does return 200 with success and error information in response.

Testing notes:

1. Create package, upload, use in bundle.
2. Fill ftrack url, service api key/username.
3. Call GET {AYON server url}/addons/ftrack/1.3.3+dev/ftrackProjects e.g. using ayon_api. If settings are set in dev or staging variant, then also add ?variant={variant} to url.
4. It should return response with project names if everything is set up correctly.

Resolves #188