Rest API: indices.delete should have "index" as a required param
[DOCS] Corrected syntax error in search curl cmd

Closes #8447
[DOCS] Expand logging documentation

Updated log4j link so it doesn't point to log4j 2.0 but version 1.2. Clarified which formats are supported and briefly explained what loggers and appenders are, plus added a link to the log4j docs.

Closes #5305
Closes #8455
Logging: Add log4j-extras dependency

Close #7927
[DOCS] Added documentation for log4j-extras dependency
Update migrate_1_4.asciidoc

Added note about MVEL being removed to breaking changes.

Closes #8462
Indices API: Fix GET index API always running all features

Previous to this change all features (_alias,_mapping,_settings,_warmer) are run regardless of which features are actually requested. This change fixes the request object to resolve this bug