Make RecordType enum names more general

[xjules]

Is your feature request related to a problem? Please describe.
RecordType is set very specifically, ie.:

class RecordType(Enum):
    f64_matrix = 1
    file = 2

and since the type is to be exploited more (in ert3) in the near future we might consider rename it for instance:

class RecordType(Enum):
    numerical = 1
    blob = 2

[pinkwah]

Make sure to allow all types:

https://github.com/equinor/ert/blob/a0e3887f89cbe06d15358c840cb9d35677aaaa2e/ert/data/record/_record.py#L55-L64

class RecordType(Enum):
    MAPPING_INT_FLOAT = 1  # List[float] and Mapping[int, float] are identical mappings
    MAPPING_STR_FLOAT = 2

    BYTES = 3

    NUMERICAL_TREE = 4
    BLOB_TREE = 5