fix vrepl: import sb { sth }

[CryingN]

In the V language's REPL, there exists:

>>> import term { red }
>>> red('test')
error: unknown function: red
    7 | import term
    8 |
    9 | red('test')
      | ~~~~~~~~~~~

>>> import term {
... red
... }
>>> red('test')
test

For the error case, I rewrote the library import logic, adding a list for each library to represent what it imports (or importing everything). The modified code resolves these issues. Due to my current limited abilities, I've also discovered some unstable hidden problems during testing. If not merged, I've also created a more aggressive fork repository vrepl for testing by replacing the vrepl program.

[huly-for-github]

Connected to Huly®: V_0.6-22716

[spytheman]

Please add a .repl test in vlib/v/slow_tests/repl/ .
You can run them with ./v vlib/v/slow_tests/repl/repl_test.v .

[spytheman]

Excellent work.