Update wiki for specific installation related items

[pjlammertyn]

• Hint for the usage of pyenv, to install the specific version of python.
• For SQL Server hint that the SQL user requires the db_ddladmin role

[pjlammertyn]

• For SQL server hint the creation of the different databases and schemas (work, omop, dqd, achilles)
• For BigQuery hint the creation of the different datasets

[kdenturc]

@pjlammertyn heb de readme reeds aangepast voor deze 4, vul je verder aan (of verbeter je zo nodig?)

[pjlammertyn]

• For SQL Server make sure the BCP tool is added to the PATH environment variable