Add 14 models and rename 1

[fwimp]

This PR adds 14 new models from #59 to rTPC and renames 1, fixing #63 .

Added

• analytiskontodimas_2004()
• ashrafi2_2018()
• betatypesimplified_2008()
• briere1_1999()
• briere1simplified_1999()
• briere2simplified_1999()
• briereextended_2021()
• briereextendedsimplified_2021()
• eubank_1973()
• janisch1_1925()
• janisch2_1925()
• taylorsexton_1972()
• tomlinsonphillips_2015()
• warrendreyer_2006()

Renamed

• modifiedgaussian_2006() -> gaussianmodified_2006()

Other

• Adds the ability to search for names matching (or nearly matching) a string or vector of strings using get_model_names()
• Fixes minor documentation formatting inconsistencies
• Updates some tests to a slightly newer format (dropping the context() function as that is now deprecated in testthat)
• Updates fit_many_models() vignette to accommodate for renaming of gaussianmodified_2006()