[swagger] List all buckets offset parameter

[gshif]

We should either remove the offset parameter from the swagger doc for GET /buckets endpoint or put a description for how this parameter is supposed to be used.

 /buckets:
    get:
      operationId: GetBuckets
      tags:
        - Buckets
      summary: List all buckets
      parameters:
          - $ref: '#/components/parameters/TraceSpan'
          - $ref: "#/components/parameters/Offset"
          - $ref: "#/components/parameters/Limit"
          - in: query
            name: org
            description: The organization name.
            schema:
              type: string
          - in: query
            name: orgID
            description: The organization ID.
            schema:
              type: string
          - in: query
            name: name
            description: Only returns buckets with a specific name.
            schema:
              type: string

 parameters:
    Offset:
      in: query
      name: offset
      required: false
      schema:
        type: integer
        minimum: 0

[vlastahajek]

Probably off-topic comment, but shouldn't swagger contain also sortBy and descending params for this endpoint (and similar with paging params)? Server supports it.