Refactor `subject_history`

This issue is derived from #9.

In general, subject_history includes patient's history records across infection, plasma isolation, virus isolation and vaccination. Those events shared attributes such as event_date, however they are mostly consisted by event-specific fields, such as vaccine_name to vaccination, or iso_name to isolation. In addition, patient's severity shouldn't attach to any of the events and should be divided into an individual table too. Here I propose to divide the subject_history into five tables + subject_treatments created by pull request #9.

My goal is to have the tables redesigned here and using a script to automatically migrate our current data.

`subject_infections`

Table for infection events. The new design allows to record re-infection events.

Field	Type	Description
`ref_name`	string	Reference name, pkey
`subject_name`	string	Subject name, pkey
`infection_date_cmp`	date_cmp_enum	Date-cmp of infection
`infection_date`	date	Date of infection, pkey
`infected_var_name`	string	Variant name (not isolate name, since the virus usually not sequenced when infected)
`location`	string	Location where the infection happened
`section`	string	Source of this data in paper

`subject_plasma`

Table for plasma isolation events. This table should also replace the main table rx_plasma.

Field	Type	Description
`ref_name`	string	Reference name, pkey
`subject_name`	string	Subject name, where the `collected_rx_name` collected from, pkey
`rx_name`	string	Plasma name (a plasma is a rx because it can be used for treatment)
`collection_date_cmp`	date_cmp_enum	Date-cmp of collection
`collection_date`	date	Date of collection, pkey
`location`	string	Location where the plasma was collected
`cumulative_group`	string	Deprecated, kept for compatible reason
`section`	string	Source of this data in paper

`subject_isolates`

Table for virus isolation events.

Field	Type	Description
`ref_name`	string	Reference name, pkey
`subject_name`	string	Subject name, pkey
`collection_date_cmp`	date_cmp_enum	Date-cmp of collection
`collection_date`	date	Date of collection, pkey
`iso_name`	string	Isolate collected
`iso_source`	string	Body source from which the isolate was obtained, should constrained by a lookup table, pkey
`iso_culture`	boolean	Whether the isolate was cultured before sequencing, pkey
`location`	string	Location where the virus isolate was collected
`section`	string	Source of this data in paper

`subject_vaccines`

Table for vaccination events. Allows infection of different vaccine on the same day.

Field	Type	Description
`ref_name`	string	Reference name, pkey
`subject_name`	string	Subject name, pkey
`vaccination_date_cmp`	date_cmp_enum	Date-cmp of vaccination
`vaccination_date`	date	Date of vaccination, pkey
`vaccine_name`	string	Vaccine name, pkey
`dosage`	int	Vaccine dosage
`location`	string	Location where the person received vaccine
`section`	string	Source of this data in paper

`subject_severity`

Table for patient's severity. Support different severity of multiple time periods. A pre-import constraint should be apply to ensure there's no overlap between records.

Field	Type	Description
`ref_name`	string	Reference name, pkey
`subject_name`	string	Subject name, pkey
`start_date_cmp`	date_cmp_enum	Date-cmp of date range start
`start_date`	date	Date range start, pkey
`end_date_cmp`	date_cmp_enum	Date-cmp of date range end
`end_date`	date	Date range end, pkey
`severity`	severity_enum	Subject severity during this time period
`section`	string	Source of this data in paper

`subject_treatments`

Table for treatments received by the patient.

Field	Type	Description
`ref_name`	string	Reference name, pkey
`subject_name`	string	Subject name, the recipient of the `rx_name`, pkey
`rx_name`	string	Treatment name, can be any CP, VP, MAb and event unclassified Rx, pkey
`start_date_cmp`	date_cmp_enum	Date-cmp of date range start
`start_date`	date	Date range start, pkey
`end_date_cmp`	date_cmp_enum	Date-cmp of date range end
`end_date`	date	Date range end, pkey
`dosage`	int	Dosage of this treatment
`dosage_unit`	dosage_unit_enum	Unit of the dosage
`section`	string	Source of this data in paper

hivdb / covid-drdb