Replace sha1 usage with safer/better hash (sha256) that is used elsewhere

[emanuelb]

sha1 function from package react-native-sha1 is used to hash BSSID in file: ./src/services/WifiService.ts https://github.com/MohGovIL/hamagen-react-native/blob/0afc8cabc4ea82c8e3ef469f19f989c8c93de24e/src/services/WifiService.ts#L4 https://github.com/MohGovIL/hamagen-react-native/blob/0afc8cabc4ea82c8e3ef469f19f989c8c93de24e/src/services/WifiService.ts#L17 https://github.com/MohGovIL/hamagen-react-native/blob/0afc8cabc4ea82c8e3ef469f19f989c8c93de24e/src/services/WifiService.ts#L28 which make additional dependency required: https://github.com/MohGovIL/hamagen-react-native/blob/40d0de490d47d53d2a005a57270b98a4176745f5/package.json#L60

sha1 function is problematic in general because it's unsafe, collisions easy to generate: https://shattered.io/ https://sha-mbles.github.io/ (in this case collisions are not likely anyway, but still it's adding additional dependency which can be avoided, see below)

also there is already usage of sha256 functions: both package sha256 https://github.com/MohGovIL/hamagen-react-native/blob/40d0de490d47d53d2a005a57270b98a4176745f5/package.json#L72 and /src/services/sha256.js file at: https://github.com/MohGovIL/hamagen-react-native/blob/c59aa1669deb2c20fbe229f65f6d812aa096df43/src/services/sha256.js which have related open issues: #151 #152 to use only 1 package instead.

fix: change all usages (sha1 & sha256) to sha256 from only 1 package (for performance & security it's better to use native implementation instead of js implementation)

[kaplanlior]

react-native-sha1 was dropped at 4ff7b4815801abac19a8f5c71cf91a317d1e12b9