Ignore DMG mounted image

If it’s a remote Time Machine Backup that is mounted, it would block for a very long time as parsing those drives take forever

(cherry picked from commit 19f9c37ced6f315c2dfb42c38821a8d4ef7a8bfe)
Mythmedatalookup: set PYTHONPATH so mythmedatalookup can be started on its own

(cherry picked from commit ab82af34abe17faa927c7ce0b8a81a5fe365773c)
Store grabber used along with inetref to ensure correct reuse.

This stores the name of the grabber that returned an inetref, prepended
to the beginning of the inetref, separate by a colon (:). This is then
used to ensure that same grabber, or one that understands its indexing,
is called any time that inetref is used. This resolves an issue where an
inetref from the Television grabber would subsequently be used to pull
data through the Movie grabber, resulting in incorrect information.

This adds a caching mechanism for the grabbers, such that the available
grabbers do not need to be rescanned each time an inetref is to be used.
This cache is expired after 60 seconds, or any time the user enters the
metadata grabber selection screen.

Fixes #12149

(cherry picked from commit e82754a7041d3988a8361535460d12a47742c65b)

Conflicts:
	mythtv/libs/libmythbase/mythversion.h
	mythtv/libs/libmythmetadata/libmythmetadata.pro
Make sure to pass season and episode to tv grabber.

Fixes #12203

(cherry picked from commit 371acd4f29ea059838d9a414fa09cca0994a5d65)
Use myth coding style

(cherry picked from commit fc8584e8b13adb31cb82290e30fa579648646ed9)
Mythmetadatalookup: Make sure we follow the exact same logic as we had prior e82754a7041d3988a8361535460d12a47742c65b

(cherry picked from commit 3c2a386e504568186209e47f0cf70372cf51f626)
Mythmetadata: Simplify code with a GetGrabber utility member

(cherry picked from commit aef97a42b3fb577dcb0d83e72c24ec3ac27602fc)
Bump ABI
Do not wait too quickly when reaching EOF

DVD Ringbuffer seeks a lot, in small files, causing the readahead to pause for one second once it reaches EOF, and preventing readsdesired to be updated. As a consequence WaitForReadsAllowed would timeout.
Also, after a seek, make sure the readahead thread is woken up, this reduce next read time by up to 1s.

Fixes #12205

(cherry picked from commit 90730e55cebf249ffb5c9cf26df2c8688f31eda4)
Player: Increase OpenFile timeout to allow playing encrypted isos on a remote FE

Signed-off-by: Lawrence Rust <lvr@softsystem.co.uk>
Signed-off-by: Jean-Yves Avenard <jyavenard@mythtv.org>
(cherry picked from commit 8945e71ed5334f08b21f177a37c7da8c8c2f57c6)