Add a noindex flag to search metadata

[PragmaTwice]

before:

tag field metadata encoding:

key (index name) | TAG_FIELD_META | field name -> separator | case sensitive

numeric field metadata encoding:

key (index name) | NUM_FIELD_META | field name -> (nil)

after:

tag field metadata encoding:

key (index name) | TAG_FIELD_META | field name -> flag | separator | case sensitive

numeric field metadata encoding:

key (index name) | NUM_FIELD_META | field name -> flag

flag:

|              8 bit              |
|---------------------------------|
|  noindex: 1bit | reserved: 7bit |

noindex indicates we don't create index for this field, which is same as in redisearch.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues

Measures
0 Security Hotspots
60.8% Coverage on New Code
1.0% Duplication on New Code

See analysis details on SonarCloud