Store plugin's scanner cache in SonarQube

Storage

Cache will be stored in SonarQubeDB, in a dedicated table. The table will contain binary data per branch.
The server doesn't know how to interpret the binary data.

SCANNER_CACHE_FILES

• branch_uuid (varchar PK)
• data (blob)

Data transfer

Scanner transfer the cache to the server in the scanner report, and gets it back through a new dedicated WS.
The data will be sent compressed, and is composed of a protobuf message containing a single key/value map.

Support / Admin

• A webservice will be created to clear the cache for all branches.
• [optional] The scanner will create a measure containing the total cache size or the size per plugin

Eviction

Eviction will be done by SonarQube when a branch or project is deleted.
Cached entries are not kept for the next analysis unless a plugin explicitly sets it again.