Listen to port 3000 instead of 8080

[hirako2000]

Many local env already listen to 8080.
Make rollup server listen to 3000 by default as it's a common dev port to use

[sasha240100]

@hirako2000 By the way, what's wrong with 8080? I guess it is aka default one

[hirako2000]

The problem with port 8080 is that:

• Some machines already listen to this port (as it's the default http port), rollup serve output stupidly fails without even saying it's because the port is already taken
• 8080 should be used for front facing production servers, not good practice for dev
• Dev common port to use is 3000, or 8000

We could use any arbitrary port, but anything is better than 8080.

[sasha240100]

@hirako2000 Merged