Add .gitignore and .gitreview files

Add the .gitignore and .gitreview files to the asterisk repo.

NB:  You can add local ignores to the .git/info/exclude file
without having to do a commit.

Common ignore patterns are in the top-level .gitignore file.
Subdirectory-specific ignore patterns are in their own .gitignore
files.

Change-Id: I2b7513fc9acf5d432cf9587c25faa9786af14abf
Tested-by: George Joseph

.gitignore

+# git ls-files --others --exclude-from=.git/info/exclude
+# Lines that start with '#' are comments.
+# For a project mostly in C, the following would be a good set of
+# exclude patterns (uncomment them if you want to use them):
+# *.[oa]
+# *~
+
+# See .gitignore in subdirectories for more ignored files
+
+*~
+*.[oadi]
+*.ii
+*.oo
+*.eo
+*.so
+*.exports
+*.moduleinfo
+*.makeopts
+*.makedeps
+makeopts
+.lastclean
+config.log
+config.status
+defaults.h
+makeopts.embed_rules
+menuselect-tree

.gitreview

+[gerrit]
+host=gerrit.asterisk.org
+port=29418
+project=asterisk.git

addons/.gitignore

+mp3

agi/.gitignore

+eagi-sphinx-test
+eagi-test
+strcompat.c

build_tools/.gitignore

+menuselect-deps

doc/.gitignore

+core-en_US.xml

include/asterisk/.gitignore

+autoconfig.h
+build.h
+buildopts.h

main/.gitignore

+asterisk
+libasteriskssl.so.1
+version.c

menuselect/.gitignore

+autoconfig.h
+cmenuselect
+config.log
+config.status
+menuselect

res/ael/.gitignore

+ael.output

utils/.gitignore

+aelbison.c
+aelparse
+aelparse.c
+ast_expr2.c
+ast_expr2f.c
+astman
+astcanary
+astdb2bdb
+astdb2sqlite3
+check_expr
+check_expr2
+conf2ael
+db1-ast/libdb1.a
+hashtab.c
+lock.c
+md5.c
+muted
+pbx_ael.c
+pval.c
+smsq
+stereorize
+strcompat.c
+streamplayer
+threadstorage.c