DOC: Document general workflows

[CJ-Wright]

Proposed workflow

Workflow 1: Obtaining Samples

1. BG student gets samples in mail
2. BG student affixes QR code to sample/sample bag
3. BG student scans into DB running in add_sample mode
4. BG student fill out resulting spreadsheet with sample info

Workflow 2: Getting ready for BT

1. BG student is going to Beamtime
2. BG student scans all the samples going to beamtime in to DB in beamtime mode
3. Software puts out beamtime sample spreadsheet
4. BG student fills out any additional info
5. BG student takes spreadsheet to BNL for loading into xpdAcq