pylint #68057 built-in checkers should use "low" base message ids, reserve some for "local use" [validation pending]

* Most of the pylint checkers have base message ids (i.e. 02 in E0213) in the low end of the range of possible two-digit base ids, 01-11. The exceptions to this are logging (65) and string_format (99). If possible, these should be renumbered to 12 and 13. (I realize it's arguably too late to rename them without breaking configuration etc.)

* A "reserved range" of base ids should be defined for local use without fear of conflicts with future checkers included with pylint. The "high numbers" (e.g 70 through 99) would be an obvious such choice, although this presumes string_format is renamed. I suppose 70-98 would be acceptable if string_format is not renamed.

* The reserved range should be documented, and the list in checkers/ should be updated.

done in0.24.0
load left0.000
closed by#51ee3f8f32c7 built-in checkers use [01-50] base message ids (closes #68057)