Phase Out Xcode Dependency GSOC Project Update

[Satryaji Aulia]

Hi all,

I'd like to write about what we've accomplished so far in this project,  
with my mentors Marcus (mcalhoun) and Clemens (cal/neverpanic).
The project's focus is to provide a smoother experience of using MacPorts  
without Xcode.

1. Opened PR for better handling of Xcode dependency [1]
In addition to the port 1.0 PortGroup, maintainers can declare Xcode  
dependency using a new Portfile option use_xcode. Unless ports declare  
Xcode dependency:
- Prefer Command Line Tools instead of Xcode by setting the DEVELOPER_DIR  
environment.
- Hide the Xcode installation when building with trace mode, so MacPorts  
can fail builds for ports that actually need Xcode but are not declared as  
such. This will help maintainers identify Xcode dependency.
Also, error out when users try to install Xcode-dependent ports without  
installing Xcode.

2. New command `port bump` to easily bump checksums of a port [2,3]
More features are planned such as @version, --livecheck, and Git actions

Please check it out, any input is appreciated. Shoutout to my mentors (and  
Mojca for reminding me to write to the mailing list).

Thank you.

[1] https://github.com/macports/macports-base/pull/130
[2] https://github.com/macports/macports-base/pull/120
[3] https://github.com/macports/macports-base/pull/127