[ZSH] Improve bare glob qualifiers

This commit...

1. Creates separate contexts and parsing rules for

   a) bare glob qualifiers `(D)`

      Bare globs may not contain characters like `(`, `)`, `~` or `|`
      to prevent ambiguities with normal shell pattern matching.

   b) extended glob qualifiers `(#qD)`

      Extended globs may contain characters like `(`, `)`, `~` or `|`,
      as `(#` is unambiguously parsed as beginning of glob flags.

   Primary point of concern are glob string quotations.

     e.g.: `(e|expr|)` is no valid glob due to `|`,
     but extended form `(#qe|expr|)` is valid.

   Note: Lookahead patterns such as `(?![{{illegal_bare_glob_chars}}])` are
   used in bare qualifiers to be able to re-use same glob string contexts
   everywhere. Alternatively all 4 string related contexts would need to be
   duplicated to only include those patterns, which are valid in bare or
   extended glob qualifiers.

2. Adds modifiers to extended parameter expansions.

   `${var:s/pat/repl/:G}`

Author: deathaxe