Expose `MedicationStatus` column in `medications` table

[milanwiedemann]

This is needed for the Pharmacy First project. We assume that the MedicationStatus has integers but we have not tested this and we do not know what they mean. We may want to consider adding this to the raw.core schema (similar to ons_deaths) for data exploration first:

• https://github.com/ebmdatalab/pharmacy-first-project/issues/10
• Slack thread: https://bennettoxford.slack.com/archives/C069YDR4NCA/p1709544965518179

[evansd]

SELECT * FROM DataDictionary WHERE [Table] = 'Medication';

Table	Type	Code	Description
Medication	DrugStatus	0	Normal
Medication	DrugStatus	4	Historical
Medication	DrugStatus	5	Blue script
Medication	DrugStatus	6	Private
Medication	DrugStatus	7	Not in possession
Medication	DrugStatus	8	Repeat dispensed
Medication	DrugStatus	9	In possession
Medication	DrugStatus	10	Dental
Medication	DrugStatus	11	Hospital
Medication	DrugStatus	12	Problem substance
Medication	DrugStatus	13	From patient group direction
Medication	DrugStatus	14	To take out
Medication	DrugStatus	15	On admission
Medication	DrugStatus	16	Regular medication
Medication	DrugStatus	17	As required medication
Medication	DrugStatus	18	Variable dose medication
Medication	DrugStatus	19	Rate-controlled single regular
Medication	DrugStatus	20	Only once
Medication	DrugStatus	21	Outpatient
Medication	DrugStatus	22	Rate-controlled multiple regular
Medication	DrugStatus	23	Rate-controlled multiple only once
Medication	DrugStatus	24	Rate-controlled single only once
Medication	DrugStatus	25	Placeholder
Medication	DrugStatus	26	Unconfirmed
Medication	DrugStatus	27	Infusion
Medication	DrugStatus	28	Reducing dose blue script

Note that the name DrugStatus here doesn't exactly match the column name MedicationStatus. But the values are in the expected range and so I think it's clear that this is the column this dictionary refers to.