Allow x-project-name property in Compose file to define project name

[shin-]

Fixes #745

Notes:

• This is not meant as an official addition to the Compose file format. Other implementations may or may not offer similar functionality.
• The order of precedence is as follows: --project-name CLI option > COMPOSE_PROJECT_NAME environment variable > x-project-name value (iff COMPOSE_X_PROJECT_NAME is enabled) > directory name

[thedeeno]

For my use case this is similar enough to using COMPOSE_PROJECT_NAME that I wouldn't get any value from these changes. Couple that with the magic _x_ prefixes and this just seems too complex to merge imo.

[jpringle03]

I would love to see this get added to Docker Compose. Is there any update on this?

[shin-]

The feedback we received on this issue led us to believe this wasn't the right approach to tackling the problem. We're still thinking about ways to do this, but I think it's safe to say this isn't it (at least not in isolation)

[jpringle03]

Thanks for the quick response @shin-

I'd love to eventually see a way to define the project name within the compose file. Is there conversation happening anywhere else about how to address this?

[ijc]

I guess this should have been closed with #5378 (comment), so I will.