Gradual introduction of New Antlr4 Parser

[tkobayas]

As discussed in https://lists.apache.org/thread/fj2vtdlmb98xlw6l97r4qscsproz0jq1 , we will introduce New Antlr4 Parser with a gradual approach.

1. Introduce the new parser(DRL10), but make it optional (not enabled by default).
2. Raise warnings when the syntax to be dropped are used in the old DRL6 parser, saying these syntax are deprecated.
   Raise warnings when DRL5 and DRL6_STRICT are used, saying these language levels are deprecated.

(six months later)

3. Raise warnings when DRL6 is used, saying DRL10 will be the default in the future : Need Create migration tools for dropped DRL syntax #6224

(six months later)

4. Make the new parser(DRL10) default

(x months later)

5. In the next major release (version 11), drop the old DRL5 andDRL6_STRICT parsers

(x months later)

6. In the major release after that (version 12), drop the old DRL6 parser, it means the deprecated syntax cannot be used at this point.

[tkobayas]

Slim down itself is handled by #6220