API Endpoint: Add custom annotations programmatically

[MattWellie]

AIP is an example of a 3rd party (relative to the Seqr front-end and main seqr-loading pipeline) source of annotations. The ideal path for this additional prioritisation could be:

1. Core pipeline runs, generating annotated joint-call
2. Seqr is loaded with the annotated joint-call
3. AIP runs, identifying variants to prioritise
4. Prioritised variants are annotated in Seqr using flags

Step 4 would enable all analysis to be done in Seqr, inc. allowing a user to filter to AIP flagged variants only.

Assumptions:

• we create a flag to use in the Seqr interface, and we expect that the flag to use would be sent as part of the API call/payload
  • are flags in Seqr represented using an int/id, or are they plaintext? e.g. is the 'flag' AIP_identified represented as that exact String, a UID, or something else
• through the API we want to trigger addition of a flag to the variant SQL DB, rather than interference with the ES index. Hopefully we can trigger the built-in process instead of having to recreate it

Params:

• Project ID (required to locate the variant within the correct joint-call)
• Variant ID
  • how is a variant uniquely identified? The URL for a variant page is chr-pos-ref-alt, but unsure if those are separate fields within the db
• family ID
• flag to use (String, ID... see above)

These could be sent as a json string, or separate URL parameters, happy to go with any guidance here

Return:

• on success: nothing/200
• on failure: 4XX & description, e.g. variant/family not found, flag doesn't exist