updated version of robyn used in budget_allocation.md; added example of robyn_allocator R script which starts from saved RDS file

updated min alpha as newer robyn requires > 0.0 for minimum; corrected typo in comment; updated robyn version to 3.5.0 (3.5.0.2 is our local build)

Added more examples of robyn_allocator

Updated budget_allocation for specific what-if scenario with excel_planning image

further research on budget_allocation including preliminary what-if

Added some work on future allocation in budget allocator

budget_allocation page added to repo with supporting data

Fixed fat-fingered variables

Added theta range in setup

Updated geometric_adstock based on corrected run without hyperparameters overly constrained.

Merge pull request #2 from DzimitryM/patch-1

Comment on geometric adstock - warning

Renamed adstock to geometric_adstock.md

findings on adstock, change label slightly.

adstock.md: some clean up of text