write down BLOBS spec into soledad documentation

gather all the BLOBS specs in a single document in soledad repo.

This is a META issue.

for reference, I think the http://soledad.readthedocs.io/en/latest/incoming_box.html gives a good structure to follow.

Sections of the spec:

• blob format: preamble and encoding.
• client transfer #8690
• client backend: sqlcipher blobs
• server backed: filesystem storage.
• sync #8966 (closed)

some known pending issues (future):

• rounding of size #8759

document also the opt-in flag to Soledad initialization (can be overriden if we find the blobs config document with a different value)

the current specs are in here: #8690 (comment 36160)

removed assignee

added Meta label

changed the description

added docs label

changed milestone to %Soledad Backlog

added API specs labels

changed milestone to %Cycle 6

changed milestone to %Cycle 7

assigned to @drebs

added mz:2.3 label

changed the description

marked the checklist item blob format: preamble and encoding. as completed

marked the checklist item client backend: sqlcipher blobs as completed

marked the checklist item server backed: filesystem storage. as completed

marked the checklist item sync #8966 (closed) as completed

marked the checklist item client transfer #8690 as completed

All items above (except for size rounding) are now part of the blobs documentation: http://soledad.readthedocs.io/en/latest/reference/blobs.html

closed