lisa._assets.kmodules.lisa: Fix and improve parsec.h

FIX

* Replace broken parse_char_in() and parse_char_not_in() by CHAR_IN()
  and CHAR_NOT_IN() optimized macros.

* Add u64 parser.

* Replace count_whitespaces with consume_whitespaces as this is the
  typical use case.

* Fix parse_buffer2charp() to guarantee it is always null-terminated.

* Add parse_buffer_strdup() that allows allocating a string with the
  content of a parse_buffer.

* Add DISCARD() combinator that discards the output and returns a void_t
  value instead.

* Add STRDUP() combinator to kmalloc a string parsed by a parser
  returning a parse_buffer.

* Kernel doc comment fixes.