Json Schema update

[isabelle-dr]

Closes #56

This Pull Request will reorganize the Json Schemas versions per folder instead of using the tags. This is done because:

• it's easier to fix errors in previous versions
• it's easier to integrate the schemas in other tools, such as the gbfs-validator

Since some fixes have been introduced in the Json Schemas used in the validator, they will be taken as the base. A review will also be done to assess changes that happened on the Json Schema repo that do not appear in the gbfs-validator repo, to make sure all fixes are included here.
This PR also addresses some of the issues and PR's related to errors in the schemas that have been open on this repository and on the gbfs-validator repository.

• Fix max_range_meters conditionally required on vehicle_types.json #45 is already fixed with the validator schemas
• Remove version field in v1.0 schema #53 is already fixed with the validator schemas
• Required fields in system_pricing_plans plan object was incorrectly placed #49 is addressed in 3ea9fac
• Fix vehicles_types_available to vehicle_types_available #50 is addressed in 175d534
• Remove vehicles from station status #55 is addressed in 454519a
• Error in schema of system_calendar gbfs-validator#45 is addressed in bb7b7b8
• Use integer type for integer fields #51 is addressed in 1937e45
• Why there is not a description of the data in system_regions schema? #48 is addressed in d95a5aa
• the version numbers have been fixed in d11cf93
• the IDs have been fixed in 37b041e
• the 2.3-RC have been added in 5af1001 and c6abba9 and
  01f3a5d