[DO NOT MERGE] Adds generate serde for PartiQL shapes.

[rchowell]

Description of changes:

• Adds linac module in partiql-beamline-serde
• Adds shape.rs (the generated sources)
• Includesruntime.rs from the codegen runtime helpers
• The file serde.rs contains the PartiqlShapeEncoder impls

Model

type shape union {

    // Any
    t_dynamic,

    // Logical
    t_unknown,
    t_bool,

    // Exact Numeric
    t_int8,
    t_int16,
    t_int32,
    t_int64,
    t_int,
    t_decimal,
    t_numeric: struct {
        precision: int,
        scale: int,
    },

    // Approximate Numeric
    t_float32,
    t_float64,
    t_float: struct { precision: int },

    // Character Strings
    t_string,
    t_string_fixed: struct { length: int },
    t_string_varying: struct { length: int },

    // Lobs
    t_blob,
    t_clob,

    // Date/Time
    t_date,
    t_time: struct { precision: int },
    t_time_tz: struct {
        precision: int,
        offset_hour: int,
        offset_minute: int,
    },
    t_timestamp: struct { precision: int },
    t_timestamp_tz: struct {
        precision: int,
        offset_hour: int,
        offset_minute: int,
    },

    // Collections
    t_bag: struct { items: shape },
    t_array: struct { items: shape },
    t_struct: struct { fields: field[] },

    // Any of
    t_union: struct { variants: shape[] },
};

type field struct {
  name: string,
  shape: shape,
};

Example

cargo run --release --all-features infer-shape -f linac  \ 
    --seed-auto --start-auto \
    --script-path ./partiql-beamline-sim/tests/scripts/sensors.ion

{
  seed: -494180438918385056,
  shapes: {
    sensors: partiql::shape::v0::'shape.t_bag'::{
      items: 'shape.t_struct'::{
        fields: [
          field::{
            name: "a",
            shape: 'shape.t_union'::{
              variants: [
                'shape.t_int64'::unit,
                'shape.t_numeric'::{
                  precision: 5,
                  scale: 4
                },
                'shape.t_float64'::unit,
                'shape.t_string'::unit
              ]
            }
          },
          field::{
            name: "d",
            shape: 'shape.t_numeric'::{
              precision: 2,
              scale: 0
            }
          },
          field::{
            name: "f",
            shape: 'shape.t_float64'::unit
          },
          field::{
            name: "i8",
            shape: 'shape.t_int64'::unit
          },
          field::{
            name: "tick",
            shape: 'shape.t_int64'::unit
          },
          field::{
            name: "w",
            shape: 'shape.t_numeric'::{
              precision: 5,
              scale: 4
            }
          }
        ]
      }
    }
  }
}

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.