WifiConfigStoreNew: Implement file write/read
Implement the file write/read for config store files. The read/write
uses the |AtomicFile| API's to perform the necessary operations.
The write is split into 2 steps to help buffering non-critical writes:
1. Serialize the data into raw bytes first.
2. Write the raw bytes to file.
Any non-critical write (indicated by |forceWrite| flag set to false)
will set an alarm to buffer all writes within the interval into a single
file write. This will also help if we want to move the actual file
writing to a separate thread later.
BUG: 29179579
Change-Id: Ib793a3967c327e13ce88acfa912c21cfa5f25865
TEST: Unit-tests
2 files changed