Clear FreeMarker and gzip caches on theme cache clear() and on startup

Closes keycloak#51066

clearCache() only cleared the theme cache, not the FreeMarker template cache or the gzip resource cache, so edited templates/resources kept serving stale content. Now it clears all three.

Also clears the cache from keycloak#52802 as suggested on the issue.

Signed-off-by: Faseela K <faseela.k@est.tech>
Signed-off-by: Alexander Schwartz <alexander.schwartz@gmx.net>
Signed-off-by: Alexander Schwartz <alexander.schwartz@ibm.com>
Co-authored-by: Alexander Schwartz <alexander.schwartz@gmx.net>

Set version to 26.8.1

Set version to 26.8.0

Set version to 26.7.5

Set version to 26.7.4

Set version to 26.6.7

Signed-off-by: stianst <stianst@gmail.com>

Set version to 26.4.16

Signed-off-by: stianst <stianst@gmail.com>

Set version to 26.7.3

Set version to 26.7.2

Set version to 26.6.6

Signed-off-by: stianst <stianst@gmail.com>