Fix certs generation

[theboringstuff]

Problem

Currently there are two problems with certs generation:

• First, it requires explicit enable/disable. This is incorrect, since certs are mandatory for site-manager webhook, so they should be ALWAYS created, either using custom certs or using certs generation.
• Currently it is allowed to disable both custom and generated certs at the same time. Also it is allowed to enable both custom and generated certs at the same time. This should not be allowed, it should be either one or another.

Solution

• Removed tls.generateCerts.enabled option from chart values. Now it is implicitly enabled by default. If custom certs are specified, generated certs get implicitly disabled.
• Updated chart templates accordingly to select custom/generated certs based on presence/absence of custom crt, key and ca
• Removed unnecessary annotations from qubership CRD
• Updated docs to remove mention of this tls.generateCerts.enabled option