lttng: list: replace domain headers with the official names

lttng: list: replace domain headers with the official names

The lttng-list command uses the following domain headers
when printing domain listings:
  - `Kernel`
  - `UST global`
  - `JUL (Java Util Logging)`
  - `LOG4j (Logging for Java)`
  - `Python (logging)`

Those don't match the official project names and/or names
used in the LTTng online documentation.

They are replaced by:
  - `Linux kernel`
  - `User space`
  - `java.util.logging (JUL)`
  - `log4j`
  - `Python logging`

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I549b309eebf0d00dfaacbed00e263f4e5e3d718b