Enhance compile subcommand functionality for projects

[jonaprieto]

Let us enhance the compile subcommand to work seamlessly with the main field in juvix.yaml as requested here,

• Use main field from juvix.yaml to specify the entry point of the program #2065

but exhibiting a behavior similar to that described for the typecheck subcommand.

• Enhance typecheck subcommand functionality for projects #2066

Expected behavior:

• If no arguments are given, it should compile the entry file specified in the main field in
  juvix.yaml (fail if there is no main field in juvix.yaml with a useful error message like
  "No entry file specified in juvix.yaml" and if juvix.yaml does not exist, saying "No
  juvix.yaml found in current directory, maybe you want to run juvix init?")

$ juvix compile

• If a path is provided, it should compile the project at that location (similarly to above)

$ juvix compile ./my-project

Note that one might tend to use . as the path to compile the current directory.

• If a filepath is given, it should compile the specified file. (Nothing should be done here,
  as this is already implemented.)

$ juvix compile ./my-project/src/Main.juvix

[jonaprieto]

Closed by

• Add main field to juvix.yaml #2120