search: delete unimplemented and now-undesired BlobTypeConstraint

The CamliType and AnyCamliType are better.

Change-Id: I0fbe9e645fa0ca13d107f7012bcb0008dfd5d43d
Adds server-side search query handler.

Change-Id: Id1bdaa0f5f5a208ccf41ce25e5c50970f66f9469
search: FileConstraint, StringConstraint, start of TimeConstraint, EXIFConstraint

Change-Id: I8464a392f2671e75898b64295b0c2e2261292ff9
Merge.

Change-Id: I15452c93c287eacf42e50dac59549a23d5e219c2