Initial memory quota implementation.

Change-Id: I49006b444724dc78bb594775a17bc281c2c1d857
Fix comment.

Change-Id: I0c70eacac6b7d8756d7ea44c6a7fa83796175472
Prep org model for memory quota implementation.

Change-Id: I8efe7091f0b207155a3e08cf606f235fe1a3ec6a
Enforce org memory quota check during app creation

Change-Id: Id24b08c4342efedb829c4212d83bb202fba59671
Move quota tests from api spec to model spec.

Change-Id: I663dc969a1f44a4cbbc54af19ffc3c011a41b242
Add free/paid quota contexts in specs.

Change-Id: I1ffcb3db6925fbb591bcc54dfd7c7f8f03b57c71
Add spec contexts for app creation and update.

Change-Id: Ib45d2cf8c47da27aeaa731357313c30523f706ee
Enforce quota check during app memory mutation.

Change-Id: Ia16fc0a7205ff482635d8c92e1a796b764f7156a
Define errors for app memory quota checks.

Change-Id: I97c14d6b6a954d0aa7d998267667042bb96e6fbf
Translate quota check sequel validation exceptions

Change-Id: Ie702dba63e7fe197cd9a182ae08f3473195b3eb7
Add api specs for app memory quota check.

Change-Id: I9b370091816f63813a20a13f1b5e812d5de7b176
Improve error message.

Change-Id: I3ae9b4d9ab82e7af5aa911ccb411cafeb92147b9