Fix keyword bloating in DEFPACKAGE :EXPORT clauses

[kilianmh]

Replace keywords in defpackage :export clauses with uninterned symbols. This avoids interning them in *package*, which should simplify autocompletion and may improve garbage collection.

[gefjon]

Can you get the symbol names in the import-from cl-ppcre clause as well?

[kilianmh]

The symbol names in the:import-from clause are now also uninterned instead of keywords.

[kilianmh]

Reverting DEFPACKAGE :IMPORT-FROM package name to KEYWORD, which should improve readability without unnecessary expansion of *PACKAGE*.