lib/oelite: Add proxy support to ftp/http/https fetcher
lib/oelite: Add proxy support to ftp/http/https fetcher

To use, either import from env by adding http_proxy, ftp_proxy, and
https_proxy to OE_ENV_WHITELIST,
OR
add http_proxy, ftp_proxy, and/or https_proxy to local.conf file.

If only http_proxy is set {ftp,https}_proxy defaults to http_proxy.

Signed-off-by: Esben Haabendal <c5ba3f1141bb30a64dd6c7e6726a53a85adc9442@prevas.dk>

sknsean/core,hundeboll/core,diorcety/oe-lite-core,sknsean/core,sknsean/core,diorcety/oe-lite-core,sknsean/core,hundeboll/core,hundeboll/core,hundeboll/core,sknsean/core