staging: Increase elasticsearch jvm heap size to half its memory
staging: Increase elasticsearch jvm heap size to half its memory

Its memory got increased from 16Gib to 32Gib.

Related to T2817

SoftwareHeritage/puppet-swh-site,SoftwareHeritage/puppet-swh-site,SoftwareHeritage/puppet-swh-site,SoftwareHeritage/puppet-swh-site,SoftwareHeritage/puppet-swh-site