memory issues after upgrading to v0.19.10

[rlindner81]

our project experienced a severe impact on memory when we upgraded hdb from v0.19.9 to v0.19.10. our servers open a little over 10k clients managed in pools for our tenants. this started to impact our server memory significantly from around 20% memory consumption, in idle, we went to >60% in idle and sometimes even crashed a server instance for non-idle.

after long sessions of rolling back individual changes, we identified the cause as
https://github.com/SAP/node-hdb/pull/238/files

we do have options.ca set to the certificate we want to use and we don't need the 147 tls root certificates "mixed in" on top. since these db connection parameters are taken directly from a hana service binding, there is no easy way for us to set options.sslUseDefaultTrustStore = false to get the old behavior back.

please turn this behavior off by default.