howto: cql: rename qname

Basic workflow

implement qname changes in backend, do not approve the pull request
implement qname changes in frontend, break the dev cluster if it is acceptable
rename qname using the test
- note: rename in each app the qname exists in
- note: server must be restared to apply new changes
approve the backend pull request, wait for server restart
Known problems

server launched with new qname changes in code before renaming the qname in the storage
both old and new qnames are exists it the system view, both has non-zero QNameIDs
only new QName exists in the AppDef
qname rename will be failed because new qname exists already
server could fail to start in the following cases:
- old name is met on recovery -> the partition is failed to start because the old QName is not found in AppDef
- async projector met an old qname -> server panics and restarts
  Solution:
launch cqlsh
- in dev cluster: cqlsh 172.17.0.1 -u cassandra -p cassandra
list existing keyspaces
```
describe keyspaces;
```
switch to the necessary keyspace
```
use <keyspaceName>;
```
save current QNameID of the old QName
- 0x00110001 is hex of uint16(17) (id of the system view for QNames) + uint16(1) (version)
- to get hex of a qname: log.Printf("0x%x", appdef.NewQName("pkg", "name"))
```
select value from values where p_key = 0x00110001 and c_col = <hex(oldQName)>;
```

set to zero QNameID of the old QName

update values set value = 0x0000 where p_key = 0x00110001 and c_col = <hex(oldQName)>;

set newQNameID = savedOldQNameID

update values set value = <oldQNameID> where p_key = 0x00110001 and c_col = <hex(newQName)>;